Showing papers on "Pulley published in 2021"

Design and Evaluation of a Novel Torque-Controllable Variable Stiffness Actuator with Reconfigurability

Abstract: The paper presents a novel reconfigurable torque-controllable variable stiffness actuator (RVSA) for knee exoskeleton. The concept of reconfiguring the pulley block is proposed to make the actuator work in different torque and stiffness ranges. The reconfigurability allows the actuator to achieve a variety of passive stiffness behaviors, namely softening, linear, and hardening behaviors. Compared with existing variable stiffness actuators based on the principle of changing the spring preload, an advantage of the RVSA is that the actuator can achieve a wider range of joint stiffness. Moreover, the RVSA model is established to study the stiffness characteristics and the ability of storing energy. The analysis results show that the RVSA can increase the number of pulley blocks to expand the stiffness range and improve the energy storage capacity. This paper also introduces a method for estimating and controlling actuator torque without using additional torque sensors. Finally, the stiffness characteristic of the RVSA is tested, and its use in a rehabilitation exoskeleton is tested. Experimental results show that the proposed torque control method is effective, and it also has a good performance in practical applications.

Trajectory Optimization for Manipulation of Deformable Objects: Assembly of Belt Drive Units

Abstract: This paper presents a novel trajectory optimization formulation to solve the robotic assembly of the belt drive unit. Robotic manipulations involving contacts and deformable objects are challenging in both dynamic modeling and trajectory planning. For modeling, variations in the belt tension and contact forces between the belt and the pulley could dramatically change the system dynamics. For trajectory planning, it is computationally expensive to plan trajectories for such hybrid dynamical systems as it usually requires planning for discrete modes separately. In this work, we formulate the belt drive unit assembly task as a trajectory optimization problem with complementarity constraints to avoid explicitly imposing contact mode sequences. The problem is solved as a mathematical program with complementarity constraints (MPCC) to obtain feasible and efficient assembly trajectories. We validate the proposed method both in simulations with a physics engine and in real-world experiments with a robotic manipulator.

Position-Tracking Control of Dual-Rope Winch Robot With Rope Slip Compensation

Abstract: This article presents the design and position-tracking control of a novel two-degree-of-freedom dual-rope winch robot. It is designed to be facilely installed at both corners of a building using two synthetic ropes and to move freely on the wall plane using the ropes to perform building maintenance work. This robot consists of a dual-rope winch system responsible for its movement on a plane and a thrust module that allows the robot to remain close to the wall through the force of the propeller. In the dual-rope winch system, ascending modules driven by two pulleys and connected by differential gears are arranged symmetrically; the position and posture on the plane can be determined by controlling the ropes. The robot winds a synthetic rope around the pulley to support the load with frictional force. Precise position control is difficult to implement because of the elasticity of the rope and the slip around the pulley. Therefore, in this article, a feedforward control to predict and compensate for the slip length of the rope and a proportional–integral controller to regulate the position error owing to the dynamic characteristics of the rope are proposed. Experiments to verify the performance of the controller for various trajectories were performed on the test bench. It was confirmed that the actual trajectory deviation is within 0.5% of the target trajectory.

Dynamic analysis of a belt transmission with the GMS friction model

Abstract: The paper presents a certain method of analysing the dynamics of a belt transmission. A flat transmission model developed by us was presented. For the analysis, it assumed the transmission 5PK belt. A discrete belt model, being a system of rigid beams interconnected with flexible and shock-absorbing elements, was used. To account for the mutual influence between the belt and pulleys, the Kelvin–Voigt contact model was used. The GMS friction model was also implemented, which allows all basic known friction phenomena to be taken into account. For this purpose, the vector of generalized coordinates was expanded with additional sub-systems of coordinates modelling the flexible belt-pulley connection. Moreover, two additional cases of a sudden transmission start were presented: with values of driving and resistance torque not causing a significant slip in the transmission as well as values of torque that cause slip.

Design of Non-Circular Pulleys for Torque Generation: A Convex Optimisation Approach

Abstract: Nowadays, robotic research focuses more and more on attaining energy-efficient and safe solutions They are key-aspects of industrial robots, such as inspection and maintenance robots The introduction of a mechanism that passively compensates the joint torque caused by the weight of the robot may offer a valid solution Avoiding the need for actuators to balance gravity torques helps decrease the power consumption and the size of the actuators Furthermore, a passive gravity compensation mechanism allows the robot to hold a static position without the need for an external power source, hence avoiding the risk of collapsing in case of failure of the actuators This work focuses on designing a torque generator composed of a non-circular pulley and a spring, which, by solving a convex optimisation problem, offers a new methodology for creating any generic torque and thereby also succeeds in solving gravity compensation problems This methodology guarantees the outcome of feasible non-circular pulleys which minimise the torque required to perform any specific task

Procedure for non-smooth contact for planar flexible beams with cone complementarity problem:

Abstract: Contact description plays an important role in modeling of applications involving flexible multibody dynamics. Example of such applications include contact between a belt and pulley, crash-worthine...

Geometric Specification of Non-Circular Pulleys Made with Various Additive Manufacturing Techniques.

Abstract: The paper presents the procedure of generating geometrical features on the contours of non-circular pulleys through the selection of materials and technological parameters for easy and efficient production of these parts Based on the models designed in the computer aided design (CAD) system, several prototype non-standard pulleys were made, which were assessed for functional characteristics and correct operation of non-linear gears The effect of additive technology on the geometric specification of non-circular pulleys was also assessed The results showed that thanks to the use of additive methods, the need for costly manufacturing of such wheels with subtractive methods was eliminated Additionally, it is not necessary to design specialized cutting tools or to use conventional or numerically controlled machine tools to manufacture these wheels The test results showed that in case of selective laser sintering (SLS) the highest accuracy of mapping (001 mm) of geometrical features of the surface was obtained This result is confirmed by the assessment of the morphology of the surface of the teeth of gears made with this technique, characterized by a uniform structure of the working surface of the wheel while maintaining a high tolerance of the outer profile of gear for selective laser sintering at the level of ±003 mm Research has shown that most of the additive methods used to manufacture non-circular pulleys meet the required geometrical features and due to the short production time of these pulleys, these methods also facilitate quick verification of the designed pulley geometry

Calibration and Analysis of Mechanical Modeling for Traction Wire Rope of Mountainous Orchard Carrier

Abstract: Low-cost transporting vehicles are a crucial routine for orchards in the mountainous place. As the core component of the mountainous orchard carrier, the wire rope is easily damaged due to frequent handling of agricultural materials. The mechanical model of carrier wire rope is the prerequisite for studying its damage mechanism. This paper first analyzes the load-bearing characteristics of the wire rope of the carrier and then uses the theory of differential geometry and the elasticity of the wire rope to establish the mechanical model of the wire rope side strand strain e0 and the axial load T of the wire rope end face in the erect state and the radial contact pressure Fa of the wire rope at the bending section and the mechanical model of the axial tension F and the pulley diameter D of the wire rope end face. On the basis of the mechanical model and the wire rope geometric solid model, the finite element stress analysis of the wire rope in the vertical state was carried out to verify the accuracy of the wire rope stress model. The results show that when the wire rope was in the vertical state, the wire-wire contact stress was linear directly proportional to the load on the end face of the wire rope; the wire-wire contact stress between the strands was about 12 times that within the strand; the average error between the simulated value and calculated value was about 13.6%, proving the correctness of the established wire mechanics model. When the rope and wheel were in contact, the contact pressure of the outer wire of the side strand was only related to the axial tension of the wire rope end face and the diameter of the pulley but not to the elasticity modulus of the pulley.

Friction lining coefficient of the drive friction pulley

Abstract: A mine hoisting system connects underground excavating areas with surface technologies; it transports extracted material, mine workers, machinery and equipment for exploitation. The main working element of mine hoisting machines is a steel wire rope, which can be wound on a drum or it can passed through a friction traction pulley. During any operation a drum hoisting system wind up one end of a hoist rope on the drum and a transport container via a cage suspension gear is gripped at the other end of the hoist rope. The rope is usually wound on the drum in one layer, but in the case of deep shafts the rope can be wound on the drum in two layers. The drum mining machines are double-acting, then the drum is divided and two hoist ropes are wound on it in two layers upper and lower. The second frequently used type of a mine hoisting equipment is a machine with a friction pulley. These machines work with a rope passing through a friction pulley KOEPPE system or friction hoist winch, where the transport vessel travels between two horizons [5, 7]. Mańka et al. specified work of mining shaft hoist, depending on the drive type: in drum drives (rope is working in the underlap or overlap arrangement) or in drives with the frictional contact (KOEPPE system) [18]. Shirong investigated the friction coefficients between the steel wire rope and Polyvinylchloride (PVC) lining [20] and the hoisting friction conditions in a mine. The measurement shown: the friction coefficient decreases with increasing velocity or pressure and distribution of friction coefficients have a log-normal distribution [20]. Chang et al. studied wear and friction characteristics of the steel wire rope and the evolution of the tribological parameters at different friction stages [6]. Guo et al. based that force direction is deflected radially to the right. Force can be distributed into normal and friction force [11]. Ma and Lubrecht studied the local contact pressure between friction lining and steel wire rope. They developed first a 2-dimensional multigrid code based on the geometry of steel wire rope [17]. Guo et al. investigated connection between friction transmission and longitudinal rope dynamics [12]. Zhang observed when steel wire rope is working around nylon pulleys; the bending fatigue life of steel wire ropes is twice longer than that of ropes working around steel pulleys [25]. In this article we describe and compare the linings of pulleys made of rubber and plastic. Standardized method [21] described in woks [1, 10] were used in the lining hardness tests. The utilization of the new lining material and development of the new lining construction lead to optimal repair maintenance [14], higher operation reliability and long life operation of the lining [15]. Material used for manufacturing of the friction lining requires high wear resistance [8] and on the other hand high friction coefficient on the contact with steel ropes. Rubber and plastic materials used for the manufacturing of the friction linings bring specific material properties [2] proper for specific operation condition of the mining hoisting system and especially for Mine hoisting KOEPPE system or friction hoist winch work with traction pulley, the pulley rim grooves are lined. Lining has to provide a higher friction coefficient between the rope and the traction pulley. The constructors of mine hoisting machines require from the manufacturers a guaranteed appropriate and stabile value of a friction coefficient at different pressures between a rope and a friction lining under different external conditions (drought, moisture, icing, etc.). The paper presents processed measurements performed on the six samples of the friction lining (G1-G6) made of rubber and the sample of the standard used friction lining (K25). The samples (G1-G6) differ in the chemical composition of the rubber. Due to the confidentiality of the material composition of the friction linings the hardness of the lining material as a discriminator was chosen. The measured values of the friction coefficient of the rubber friction lining samples were compared with the values of the friction coefficient of the friction lining (K25) usually mounted on friction lining pulley. Highlights Abstract

Design of a Free Energy Generator using Gravity Wheel & Dynamo

Abstract: This paper presents an investigation and design of a free energy generator using dynamo and gravity wheel/ flywheel arrangement. This paper proposes a method to produce energy which is called free, as we have to pay zero after certain conditions. Due to the friction in dynamo, the lost energy is used for the generation of free energy. This energy will be utilized to operate other electrical equipment. It consists of a single-phase motor which is used to drive the mechanical arrangement of pulley drive and belt. As a result, the shaft rotates on which the wheel is mounted. The remarkable mechanism about this design is that more significant electrical power can be obtained. It is done with the help of a flywheel. The flywheel is combined with the rigging-train to generate free energy. The consequences of design testing show that this vitality alternative is reasonable and it isn't dependent upon climatic conditions.

Kinematics of Elastic Tendons for Tendon-Driven Manipulators with Transmission Friction

Abstract: This paper proposes a novel differential kinematics of elastic tendons for tendon-driven manipulators where tendons transmit actuator force/torque to remote links via a train of pulleys. The local variability of tension and longitudinal speed in each tendon is carefully investigated in terms of the rest lengths of the virtually partitioned tendon segments along the tendon. A significant attention is paid to building a proper friction-tension mechanic model between the pulleys and tendons to identify the no-slip points that are important to be used as kinematic constraints. The kinematic relations of tendon are obtained for two possible types of tendon-pulley transmission, i.e., free-free ended and fixed-free ended types, and then a complete kinematics of tendon is formulated by augmenting all the kinematic relations existing in the entire system. Simulation and experimental results are provided to validate the proposed kinematics of tendon by comparing with a previous simple spring model where the tension was determined by the relative positions of consecutive pulleys.

Motor Current Based Force Control of Simple Cable-Driven Parallel Robots

Abstract: State of the art cable-driven parallel robots achieve high precision and reliability using a complex setup. The complexity results largely from the integration of force sensors which are omitted in the presented design. Instead, a motor current based approach is proposed to determine the cable forces. Therefore, methods are employed to compensate the cogging torque of the motor and frictional forces along the transmission path from the motor torque to the acting force at the platform. Despite the compensation, it is useful to reduce the overall frictional forces. Therefore, a gearless design scheme with a single pivoting pulley for cable guidance is realized. The proposed approach enables the application of advanced control methods for simple cable-driven robots.

MRI of Finger Pulleys at 7T-Direct Characterization of Pulley Ruptures in an Ex Vivo Model.

Abstract: The aim of this study was to evaluate 7 Tesla (7T) magnetic resonance imaging (MRI) for direct visualization and specific characterization of the finger flexor pulleys A2, A3, and A4 before and after ex vivo pulley rupture. Thirty fingers of human cadavers were examined before and after pulley disruption with a 26 min clinical 7T pulse sequence protocol. Images were assessed by two experienced radiologists for the presence of pulley rupture. Injury characterization included definition of rupture location, morphology, and complications. Image quality was evaluated according to a 4-point Likert-type scale from “not evaluable” to “excellent”. Macroscopic preparations were used as the reference standard. Direct characterization of intact A2, A3, and A4 pulleys and the corresponding pulley lesions was possible in all cases. The rupture location was distributed equally at the radial, ulnar, and central parts of the pulleys. A dislocation and intercalation of the pulley stump between the flexor tendon and finger phalanges was observed as a complication in 62.5% of cases. The average Likert score for direct visualization of pulleys was 2.67 before rupture and 2.79 after rupture creation, demonstrating adequate image quality for routine application. 7T MRI enables a direct characterization of A2, A3, and A4 pulleys before and after artificial disruption, including the definition of rupture morphology and location as well as the detection of rupture complications. This promises a precise presurgical evaluation of pulley injuries and complicated pulley stump dislocations.

Velocity Based Hybrid Position-Force Control of Cable Robots and Experimental Workspace Analysis

Abstract: One important design criteria of a cable-driven parallel robot is its workspace. Disturbance effects on drive systems, pulley mechanisms and cables have a major impact on the workspace due to their influence on cable forces. Thus, the computed wrench-feasible workspace with ideal kinematic constraints may not be valid while operating the platform of a cable robot. To ensure that the platform moves within the workspace, cable forces can be controlled, whereby kinematic inaccuracies such as calibration errors affecting the platform’s positional accuracy. Hence, in this paper a concept of the velocity based hybrid position-force controller is presented in order to pretension cable forces on one hand, and ensure positioning accuracy on the other hand. The controller stability is investigated on extreme poses outside the wrench-feasible workspace hull of a dynamic model of a planar cable robot in simulation environment. Thereupon, the hybrid controller was implemented in a real-time control system and analyzed on the cable robot setup COPacabana with experiments inside and outside the computed workspace border. The analysis of measured signals is based on statistical investigation by performing multiple measurements of the same platform trajectory. Both, simulation and experiments show that the proposed velocity based hybrid position-force controller is feasible and can be applied to move the platform outside the workspace.

Investigation on the Rotational Dynamics of a Timing Belt Drive Including an Oval Driving Pulley

Abstract: Recent developments in timing belt drive for the automotive engine have seen the use of non-circular pulleys. This study presents an experimental and numerical investigation on this type of transmission including an oval pulley. A specific test rig has been designed to enable the identification of the proper effect of an oval pulley on the transmission dynamics. The belt tensions, the speeds, and torques of the driving and driven pulleys were measured and analyzed for three different transmission configurations: (1) circular driving pulley and oval driving pulley without (2) and/or with (3) load torque applied. Analyses were carried out in the time and frequency domains by considering the driving pulley rotation angle as a reference. In parallel a numerical model has been developed, it accounts for the specific motions of the belt seating/unseating points on the oval pulley and its neighboring pulleys. The model considers the variation of lengths for the belt spans adjacent to the oval pulley. This induces variable longitudinal stiffness and influences the transmission dynamics that is predicted versus time and compared with experiments. The phasing angle of the oval driving pulley was adjustable in order to study its influence. With no resistant torque applied, it was found that, for low-speeds, the oval pulley has a pure kinematic effect on the transmission dynamics. When a load torque is applied, the effectiveness of the oval pulley regarding the belt tensions and transmission error fluctuations is verified experimentally for some specific intervals of the phasing angle.

Tension management in cable transmission systems for remote manipulators

Abstract: This paper presents the design of a novel kinematic tensioning system to remedy the situation where the input-output relation in the cable transmission for a remotely operated multi-link end-effector is compromised due to the onset of slack. The actuation of multi-link end-effectors in remote manipulators via cable transmission exhibits loss of tension and slack generation on the non-driving side of the cable transmission. This paper outlines an analytical formulation of the kinematic component of slack resulting from the geometry of the end-effector links that are serially connected. If left unaddressed, cable slack adversely impacts transmission stiffness and produces backlash at the end-effector wherein for a fixed input, the output can move freely over a range of motion (i.e. dead-band). In case of articulating instruments for minimally invasive surgery, this limits the ability to position and orient the end-effector precisely, the ability to effectively transmit forces via the end-effectors to the surrounding tissues, and the tactile feedback to the user operating the instrument. To overcome these limitations, this paper presents a simple solution that effectively mitigates slack on the non-driving side of a cable transmission between a driving pulley and a multi-link end-effector with minimal cost or complexity. The proposed design uses a driving pulley modified with tensioner extensions to alter the transmission path, which provides a kinematic or geometric solution in contrast to the various spring based solutions that have several drawbacks. Based on a derivation of slack in the system, a design optimization is performed to generate the key dimensions of the tensioning system that minimizes slack without causing over-constraint. An experimental setup is designed and fabricated to validate the slack predictions in the cable transmission system for a multi-link end-effector, without and with the proposed tensioner. The experimental measurements demonstrate the efficacy of the proposed solution.

Use of Thermoplastic Rings Following Venting of Flexor Tendon Pulleys: A Biomechanical Analysis.

Abstract: Purpose Normal digital flexion relies on flexor tendon pulleys to convert linear muscular force to angular digital motion. However, there is a growing trend to vent them partially during flexor tendon repair. The objective of this study was to examine the effects of a thermoplastic ring, acting as an external pulley, on flexor tendon biomechanics and finger range of motion (ROM) after pulley venting. Methods We tested 15 cadaveric digits using an in vitro active finger motion simulator. We measured loads induced by flexor digitorum superficialis (FDS) and flexor digitorum profundus (FDP) as well as joint ROM with sequential sectioning of the A2, A3, and A4 pulleys compared with an intact pulley condition. At each stage, external thermoplastic pulley rings were applied snugly over the proximal and middle phalanges to recreate A2 and A4 function, respectively. Results After complete venting of the A2, A3, and A4 pulleys, proximal interphalangeal joint ROM significantly decreased by 13.4° ± 2.7° and distal interphalangeal joint ROM decreased by 15.8° ± 2.1°. Application of external rings over the proximal and middle phalanx resulted in a residual ROM decrease of 8.3° ± 1.9° at the proximal interphalangeal joint and 7.9° ± 2.1° at the distal interphalangeal joint, nearly restoring ROM. Similarly, complete pulley venting resulted in reduced FDS load by 37% and FDP load by 50% compared with intact pulleys. After application of external rings, loads were restored almost to normal, with a 9% reduction for FDS load and 9% reduction for FDP load compared with intact pulleys. Conclusions The application of thermoplastic rings acting as external pulleys is an effective, noninvasive, and reproducible approach to restore flexor tendon biomechanics and digit ROM after pulley venting. Clinical relevance Thermoplastic rings may be a useful therapeutic adjunct in restoring joint ROM and flexor tendon loads after surgical venting of the pulleys.

New Sensor Device to Accurately Measure Cable Tension in Cable-Driven Parallel Robots.

Abstract: Cable-driven parallel robots are a special type of robot in which an end-effector is attached to a fixed frame by means of several cables. The position and orientation of the end-effector can be controlled by controlling the length of the cables. These robots present a wide range of advantages, and the control algorithms required have greater complexity than those in traditional serial robots. Measuring the cable tension is an important task in this type of robot as many control algorithms rely on this information. There are several well-known approaches to measure cable tension in cable robots, where a trade-off between complexity and accuracy is observed. This work presents a new device based on strain gauges to measure cable tension specially designed to be applied in cable-driven parallel robots. This device can be easily mounted on the cable near the fixed frame, allowing the cable length and orientation to change freely, while the measure is taken before the cable passes through the guiding pulleys for improved accuracy. The results obtained from the device show a strong repeatability and linearity of the measures

An Emergency Strategy for Cable Failure in Reconfigurable Cable Robots

Abstract: This paper investigates cable failure and an emergency strategy for reconfigurable cable-driven parallel robots (CDPRs). Reconfiguration of CDPRs is a key feature to avoid collisions, which is currently applied e.g. in prototypes for automated construction tasks. This paper proposes to utilize this ability within an emergency strategy based on minimization of the kinetic energy, which is extended to include movable pulleys on actuated linear slides. The paper analyzes the static equilibrium workspace with constant orientation of a prototype both pre- and post-failure. Based on global numerical optimization, a geometric reconfiguration is proposed to restore most of the workspace after failure. Furthermore, within a dynamic simulation, the extended strategy is evaluated for dynamically moving pulleys. Finally, the results are compared to a simulation with fastened pulleys.

Bahadur efficiencies of the Epps--Pulley test for normality

Abstract: The test for normality suggested by Epps and Pulley (1983) is a serious competitor to tests based on the empirical distribution function. In contrast to the latter procedures, it has been generalized to obtain a genuine affine invariant and universally consistent test for normality in any dimension. We obtain approximate Bahadur efficiencies for the test of Epps and Pulley, thus complementing recent results of Milosevic et al. (2021). For certain values of a tuning parameter that is inherent in the Epps--Pulley test, this test outperforms each of its competitors considered in Milosevic et al. (2021), over the whole range of six close alternatives to normality.

Using a simple rope-pulley system that mechanically couples the arms, legs, and treadmill reduces the metabolic cost of walking.

Abstract: Emphasizing the active use of the arms and coordinating them with the stepping motion of the legs may promote walking recovery in patients with impaired lower limb function. Yet, most approaches use seated devices to allow coupled arm and leg movements. To provide an option during treadmill walking, we designed a rope-pulley system that physically links the arms and legs. This arm-leg pulley system was grounded to the floor and made of commercially available slotted square tubing, solid strut channels, and low-friction pulleys that allowed us to use a rope to connect the subject’s wrist to the ipsilateral foot. This set-up was based on our idea that during walking the arm could generate an assistive force during arm swing retraction and, therefore, aid in leg swing. To test this idea, we compared the mechanical, muscular, and metabolic effects between normal walking and walking with the arm-leg pulley system. We measured rope and ground reaction forces, electromyographic signals of key arm and leg muscles, and rates of metabolic energy consumption while healthy, young subjects walked at 1.25 m/s on a dual-belt instrumented treadmill (n = 8). With our arm-leg pulley system, we found that an assistive force could be generated, reaching peak values of 7% body weight on average. Contrary to our expectation, the force mainly coincided with the propulsive phase of walking and not leg swing. Our findings suggest that subjects actively used their arms to harness the energy from the moving treadmill belt, which helped to propel the whole body via the arm-leg rope linkage. This effectively decreased the muscular and mechanical demands placed on the legs, reducing the propulsive impulse by 43% (p < 0.001), which led to a 17% net reduction in the metabolic power required for walking (p = 0.001). These findings provide the biomechanical and energetic basis for how we might reimagine the use of the arms in gait rehabilitation, opening the opportunity to explore if such a method could help patients regain their walking ability. Trial registration: Study registered on 09/29/2018 in ClinicalTrials.gov (ID—NCT03689647).

Trajectory Optimization for Manipulation of Deformable Objects: Assembly of Belt Drive Units

Abstract: This paper presents a novel trajectory optimization formulation to solve the robotic assembly of the belt drive unit. Robotic manipulations involving contacts and deformable objects are challenging in both dynamic modeling and trajectory planning. For modeling, variations in the belt tension and contact forces between the belt and the pulley could dramatically change the system dynamics. For trajectory planning, it is computationally expensive to plan trajectories for such hybrid dynamical systems as it usually requires planning for discrete modes separately. In this work, we formulate the belt drive unit assembly task as a trajectory optimization problem with complementarity constraints to avoid explicitly imposing contact mode sequences. The problem is solved as a mathematical program with complementarity constraints (MPCC) to obtain feasible and efficient assembly trajectories. We validate the proposed method both in simulations with a physics engine and in real-world experiments with a robotic manipulator.

Overhead transmission line patrol robot

Abstract: The utility model relates to a line patrol robot for an overhead transmission line, and belongs to the technical field of special line patrol machines for power transmission. According to the technical scheme, a lifting driving motor (304) is started, a pulley (403) is lifted up, an operator puts a cable of an overhead power transmission line into a mechanical foot frame (401), the pulley (403) isdescended, the cable is located between a pulley groove of the pulley (403) and a lower layer plate, and the placement work of one mechanical foot is completed; repeating the operations until all themechanical feet are placed; the mechanical foot driving motor (406) rotates forwards to drive the pulley to act, so that the robot moves forwards, and the mechanical foot driving motor rotates reversely to drive the pulley to act reversely, so that the robot moves backwards; and a ground operator acquires an image or a video image through the detection module (7) to complete routing inspection. The obstacle crossing inspection robot has the positive effects that obstacle crossing inspection can be completed by sequentially controlling lifting and moving of the mechanical feet when obstacles such as a vibration damper, a spacer and a tower cross arm are met.

Cable robot movement system using adjustable supports

Abstract: A cable robot system may be used to clean a building. The system may comprise a central element 1 connected to a plurality of cables 2 which may be connected to a plurality of winches or pulleys 3 located at the edges or corners of a building. The central element may be steered or guided around the face of the building by selectively operating the winches to shorten or lengthen cables 2 and by use of an intermediate wheel like support 5 that is located on each of the cables. The central support means may have a telescopic arm (1, Fig 5) and may be fitted with a pulley (7, Fig 2) or a winch means (6, Fig 3). The central element may be fitted with repair and cleaning tools such a brushes and/or nozzles, and/or painting, plastering tools.