Showing papers on "Pulley published in 2019"

Medical systems incorporating pulley sharing

Abstract: Provided is a robotic system that includes a surgical instrument with a wrist that allows N degrees of freedom of movement. The N degrees of freedom can be controlled by N+1 cable segments. The wrist can include a first set pulleys configured to rotate about a first axis and a second set of pulleys configured to rotate about a second axis. The wrist can further comprise one or more pulleys configured to engage two of the cable segments, wherein at least one of the pulleys is shared by a first cable segment and a second cable segment. The first cable segment and the second cable segment that share the pulley can be independent from one another. In some circumstances, the surgical instrument can be actuated in N+1 degrees of movement by advancing or retracting at least two of N+1 cable segments.

Robotic medical systems with high force instruments

Abstract: A robotic system can include a high force instrument that amplifies input forces such that output forces are greater than input forces. The high force instrument can include an end effector. The high force instrument can further include a first pulley configured to rotate about a pulley axis and a first jaw member connected to the first pulley by a first drive pin. The high force instrument can also include a second pulley configured to rotate about the pulley axis and a second jaw member connected to the second pulley by a second drive pink. A link can provide a first pivot point about which the first jaw member can pivot and a second pivot point about which the second jaw member can pivot.

Exact Kinematic Modeling and Identification of Reconfigurable Cable-Driven Robots With Dual-Pulley Cable Guiding Mechanisms

Abstract: Cable guiding mechanisms (CGMs) directly influence the reconfigurability of cable-driven parallel robots (CDPRs). But due to the complicated kinematic model of pulley-based CGMs, the velocity and acceleration mappings from the moving platform (MP) to the cables were unknown, the continuity of cable velocity, acceleration, and tension was unguaranteed, and the calibration pose-search method was based on inaccurate CGM models. In this paper, we establish an analytic and compact model for CGM. Based on this model, the velocity and acceleration mappings from the MP to the cables are derived. The continuities of cable trajectory and tension are proved. The exact identification Jacobian and its derivative are also formulated, leading to the increased fidelity of pose-search methods. The proposed method and formulations are verified by simulations and experiments on a redundant CDPR.

Manually and robotically controllable medical instruments

Abstract: Certain aspects relate to manually and robotically controllable medical instruments. A manually and robotically controllable medical instrument can include an elongated shaft articulable by pull wires. The elongated shaft can be connected to an instrument handle that attaches to an instrument drive mechanism. The instrument handle can include a pulley assembly on which the pull wires can be mounted. Rotation of the pulley assembly can actuate the pull wires to cause articulation of the elongated shaft. The medical instrument also includes a manual drive input connected to the pulley assembly such that manual actuation of the manual drive input causes rotation of the first pulley assembly and a robotic drive input configured to engage with a robotic drive output of the instrument drive mechanism such that rotation of the first robotic drive output causes rotation of the pulley assembly.

Medical instruments for tissue cauterization

Abstract: Certain aspects relate to systems and techniques for an articulating monopolar medical instrument. In one aspect, the medical instrument includes a wrist comprising a proximal clevis and a distal clevis; an end effector coupled to the distal clevis via a distal axle; at least one proximal pulley in the proximal clevis; at least one distal pulley in the distal clevis and coupled to the distal axle; a first cable configured to engage with the at least one proximal pulley and the at least one distal pulley; and a second cable configured to engage with the at least one proximal pulley without engaging the at least one distal pulley.

Artificial Neural Network Based Fault Diagnosis of a Pulley-Belt Rotating System

Abstract: Rotating machines are widely used in various industrial fields. Hence, an unexpected stoppage due to, for example, bad operating conditions or manufacturing error, has safety implications along with economic considerations. In this research, a fault detection system for a pulley-belt rotating system is developed and then different faults simulated in a test rig are investigated. Vibration signal monitoring is utilized since it represents a reliable approach for fault recognition in rotating machinery. Time-domain signal analysis technique is applied to extract some indicative features, such as root mean square, kurtosis and skewness. An artificial neural network (ANN) model is developed to detect the simulated faults. However, in addition to the machine healthy condition five fault types, such as unbalance in the driving pulley, wear in the belt and pulleys misalignment, have been simulated in the test rig. Two MEMS accelerometers (ADXL335), interfaced to Arduino MEGA 2560 as a data acquisition device, are used for vibration amplitude measurement. LabVIEW, which is a graphical programming software, is utilized to develop a signal capturing, analysis and feature extraction system. The result showed the effectiveness of the developed system in detection of different fault types in the pulley-belt system.

Indirect Force Control of a Cable-Driven Parallel Robot: Tension Estimation using Artificial Neural Network trained by Force Sensor Measurements.

Abstract: In a cable-driven parallel robot (CDPR), force sensors are utilized at each winch motor to measure the cable tension in order to obtain the force distribution at the robot end-effector. However, because of the effects of friction in the pulleys and the unmodeled cable properties of the robot, the measured cable tensions are often inaccurate, which causes force-control difficulties. To overcome this issue, this paper presents an artificial neural network (ANN)-based indirect end-effector force-estimation method, and its application to CDPR force control. The pulley friction and other unmodeled effects are considered as black-box uncertainties, and the tension at the end-effector is estimated by compensating for these uncertainties using an ANN that is developed using the training datasets from CDPR experiments. The estimated cable tensions at the end-effector are used to design a P-controller to track the desired force. The performance of the proposed ANN model is verified through comparisons with the forces measured directly at the end-effector. Furthermore, cable force control is implemented based on the compensated tensions to evaluate the performance of the CDPR in wrench space. The experimental results show that the proposed friction-compensation method is suitable for application in CDPRs to control the cable force.

Geometric Control and Differential Flatness of a Quadrotor UAV with Load Suspended from a Pulley

Abstract: We study a quadrotor with a cable-suspended load, where the cable length can be controlled by applying a torque on a pulley attached to the quadrotor. A coordinate-free dynamical model of the quadrotor-pulley-load system with nine degrees-of-freedom and four degrees-of-underactuation is obtained by taking variations on manifolds. Under the assumption that the radius of the pulley is much smaller than the length of cable, the quadrotor-pulley-load system is established to be a differentially-flat system with the load position, the quadrotor yaw angle and the cable length serving as the flat outputs. A nonlinear geometric controller is developed, that enables tracking of outputs defined by either (a) quadrotor attitude, (b) load attitude, (c) load position and cable length. Specifically, the design of the controllers for load position and cable length are taken into consideration as a whole unit due to the dynamical coupling of the quadrotor-pulley-load system. Stability proofs for the control design in each case and a simulation of the proposed controller to navigate through a sequence of windows of varying sizes is presented.

Design of a 3D-printable, robust anthropomorphic robot hand including intermetacarpal joints

Abstract: This paper presents a new mechanical design of an anthropomorphic robot hand. The hand is designed such that it is adaptive, backdrivable, modularized to provide both dexterity and robustness. The hand has 18 joints, 14 degrees of freedom, and a new joint mechanism called an active DIP–PIP joint for the robot finger. The mechanism includes a pair of movable pulleys and springs for generating both linked and adjustable motions. Although the set of DIP (distal interphalangeal) and PIP (proximal interphalangeal) joints exhibits a coupled movement in free space, it moves adaptively when it contacts an object. To ensure a 1:1 ratio movement when a finger is moving freely and to produce additional joint torque when gripping an object, torsion springs are attached to each joint. The backdrivability of each joint is realized using an actuation module with a miniature BLDC motor and a ball screw. In addition, the relatively unknown intermetacarpal joints, which provide additional dexterity to the hand for grasping small objects, are used in the robot hand model. A modularized design simplifies the assembly of the hand and increases the economic feasibility. Experimental results are included in this paper for validating the design of the robot hand.

Human string-pulling with and without a string: movement, sensory control, and memory.

Abstract: String-pulling is a behavior that is allied to many daily acts and is an easily performed action featuring hand-over-hand movements to reel in a string (or rope). String-pulling has been used as a test of perceptual and cognitive functions in many animal species, including human children, but its movements and sensory control have not been characterized. Male and female university students (n = 68) performed target-based or memory-based string-pulling in which they pulled down a string suspended on an overhead pulley and immediately afterwards attempted to make the same movement in a memory-based test. Frame-by-frame video scoring was used to describe movements, eye-tracking and visual occluding glasses were used to assess sensory control, and a Matlab video-analysis procedure was used to describe kinematics. The string was advanced using five arm/hand movements: with lift and advance comprising fast up movements, and grasp, pull and push comprising slow down movements. Fingers closed 5 (pinky) through 1 (thumb) to make a whole-hand grasp and release in target-based string pulling but moved in a reverse sequence for the memory-based task. Target-based string pulling was not visually guided unless participants were instructed to grasp at a cue, and then vision featured eye-tracking of the target and pupil dilation with the grasp, but there was no relation between eye events for memory-based string-pulling. For target-based string-pulling the left and right hands advanced the string with both independent and concurrent movement but only independent movements were featured in a more symmetrical memory-based movement. The results are discussed in relation to the sensory control of hand movements, contemporary theories of the neural control of hand movements, and species differences in string-pulling.

Bidirectional Spiral Pulley Negative Stiffness Mechanism for Passive Energy Balancing

Abstract: The energy balancing concept seeks to reduce actuation requirements for a morphing structure by strategically locating negative stiffness devices to tailor the required deployment forces and moments. One such device is the spiral pulley negative stiffness mechanism. This uses a cable connected with a pre-tension spring to convert the decreasing spring force into the increasing balanced torque. The kinematics of the spiral pulley is first developed for bidirectional actuation, and its geometry is then optimized by employing an energy conversion efficiency function. The performance of the optimized bidirectional spiral pulley is then evaluated through the net torque, the total required energy, and energy conversion efficiency. Then, an additional test rig tests the bidirectional negative stiffness property and compares the characteristics with the corresponding analytical result. Exploiting the negative stiffness mechanism is of significant interest not only in the field of morphing aircraft but also in many other energy and power reduction applications.

Belt-Drive Mechanics: Friction in the Absence of Sliding

Abstract: Recent studies have shown that steady and unsteady operation of a belt drive may exhibit regimes absent of sliding at the belt–pulley interface, where instead detachment waves serve to relax stress in the so-called “slip” arc. To explore this finding further, herein we present an experimental and theoretical investigation into frictional mechanics in a simple belt drive system. To estimate friction experimentally, we perform a stress analysis based on spatio-temporal measurements of the belt tension, traction, and contact area evolution. Subsequently, we develop a model taking into account both bulk and surface hysteretic losses to explain the experimental observations. Our results show that the shear strain at the belt–pulley interface differs significantly between the driver and the driven pulleys, resulting in much larger mechanical losses in the driver case. The shear strain drops at the transition from the adhesion to the slip arc, and, in contrast to accepted theories, the slip arc contributes little to nothing to the power transmission. Our model reveals that the contact area evolution correlates to the shear traction changes and that viscoelastic shear and stretching dominate in the belt rolling friction. A significant contribution of detachment waves to the energy dissipation explains the higher mechanical losses observed in the driver case.

Modelling a timing belt pitch

Abstract: The paper deals with the problem of timing belt pitch significance for the dynamics of a timing belt transmission gear motion. Specific pitches of timing belts have been used for many years. They were previously reserved for belts made of rubber, while another group of pitches was intended for belts made of polyurethane. This division ceased to apply recently, and in addition there are belts with pitches which have not been used before, such as HTD9M or AT15. The paper presents the parameter that makes the pulley diameter and the pitch dependent on the number of teeth involved in meshing (coupling) with a pulley. It is an equivalent of the coverage factor occurring in cylindrical timing gears. Earlier studies on that parameter did not take into account the teeth unevenly spaced over the width of the belt. New pitches of belts may occur in "mass production" applications and they are applied more and more often. Thus it is important to bear in mind the consequences of changing the pitch of the timing belt in transmission gear structures.

A Motion Transmission Model for a Class of Tendon-Based Mechanisms With Application to Position Tracking of the da Vinci Instrument

Abstract: Tendon-based motion/force transmission is a conventional approach in the design of surgical robots. However, due to compliance in the tendons and significant frictions between the tendons, the pulleys, and the sheath, tendon-based systems exhibit highly nonlinear behavior that, in particular, includes hysteresis. In this paper, based on the concepts of creep theory in belt drive mechanics, a novel motion transmission model is developed for tendon-pulley mechanisms. The developed model is of pseudokinematic type; specifically, it relates the output displacement to both the input displacement and the input force. The model parameters are identified for a da Vinci instrument, and the model performance is experimentally evaluated. The experimental results demonstrate greater than 50% improvement in terms of root-mean-square position error as compared to a more conventional friction/compliance-free kinematic model. The model is subsequently used for position control of the tip of the instrument, resulting in elimination of the hysteresis and in accurate trajectory tracking.

Sports moving arm trainer of doing all can

Abstract: The utility model discloses a sports moving arm trainer of doing all can, including bottom plate, L template, second spiral shell rasp bar, motor, belt pulley, belt, loading board, balancing weight, haulage rope, hand power ring, reel, L type bracing piece, electric putter and running -board, the multifunctional medical pager is diversified in function, actions such as chin is carried out throughthe horizontal bar, temper the arm strength, and can the starter motor, the transmission coordination that the motor passes through belt pulley and belt drives the synchronous rotation of two second spiral shell rasp bar, adjust the height of horizontal bar, adapt to the not people's of height demand, and realizing high adaptability, can also pass through L type bracing piece and running -board, carry out the exercise of push -up, height through electric putter adjustment running -board, adjust the training intensity of push -up, can also stimulate the hand power ring, temper the arm strength,can be through the position of adjustment mounting panel, thereby can select different angles pulling mode, can temper the polylith muscle on the arm, training effect has been improved more.

Development of Novel Bevel-Geared 5 mm Articulating Wrist for Micro-Laparoscopy Instrument

Abstract: A laparoscopic surgery can be made less invasive by utilizing slimmer tools However, at the size scale of the microlaparoscopic instruments, it has been very challenging to incorporate a wrist mechanism for dexterous manipulation at the surgical sites In this letter, we present a 5-mm wristed instrument for microlaparoscopy Unlike other instruments with wrists utilizing the bending of compliant parts or tendon and pulleys, the instrument has a wrist mechanism using oblique bevel gears driven by two concentric shafts As a result, the wrist can generate a 2-degrees-of-freedom sharp articulating motion with 1) pitch angle range of ±90° and 2) a full rotation along roll direction Also, the wrist is scalable and easier to assemble compared to the ones using tendon and pulleys The accuracy and the load carrying capacity of the wrist were evaluated The wrist was able to orient tools to the commanded direction with an average error of 131° and manipulate up to 250 g of the load The feasibility of the instrument was verified through pick and place experiment and peg transfer test using a teleoperated surgical robot equipped with the instrument Using the single robot arm with the proposed wrist, it took 987 s on average to transfer five objects consecutively to the opposite side of the pegboard Thus, the articulating wrist widens dexterity in tight anatomic space with the oblique gear mechanism It is applicable to needlescopic instruments or steerable laparoscope system

Intelligent environmental-friendly spraying line for combined multi-functional individual comprehensive training device

Abstract: The invention relates to the technical field of paint spraying, and discloses an intelligent environmental-friendly spraying line for a combined multi-functional individual comprehensive training device. The intelligent environmental-friendly spraying line for the combined multi-functional individual comprehensive training device comprises a frame body, wherein rotary shafts are rotatably connected to the left side and the right side of the middle part of the frame body; fixed bases are fixedly connected to one sides, close to the middle, of the rotary shafts, and are fixedly connected with aprocessing piece; a first drive motor is fixedly connected to the left side of the bottom part of the frame body; and a first belt pulley is fixedly connected to an output shaft of the first drive motor and is connected with a second belt pulley through a belt. The intelligent environmental-friendly spraying line for the combined multi-functional individual comprehensive training device provided by the invention is applied to a spraying device; through arranging a screw rod and sliding block, the sliding block can move left and right on the upper part of the processing part; through arranginga grinding head and a spraying head, the process piece can be ground and paint-sprayed in one device, and two processing types can be accomplished through one-time clamping, so that the processing time is saved; in addition, a paint spraying effect of the ground processing piece is remarkably improved, so that the product quality is improved; and the whole device is simple to use, reasonable in design and suitable for popularization and use.

Steel construction surface paint device

Abstract: The utility model discloses a steel construction surface paint device, including second band pulley, second mount, casing, casing one side front portion is provided with the second mount, keep away from at second mount rear casing one side is provided with the second band pulley, second band pulley rear is provided with the fourth mount, keep away from at fourth mount rear casing one side is provided with the fixed block. Beneficial effect lies in: 1, through setting up the 3rd electric putter adjustment distance, a servo motor drives grinding wheel drives the oxide layer on steel surface, prevent to use to paint after a period and drop, be favorable to improving the life of steel, 2, through setting up the dust that produces when air purifier can purify when spraying paint more volatile toxic gases and grinding, the pollution to the environment is reduced, prevent to cause harm to staff's health, 3, it is dry through setting up air heater blowing hot air, can make curable paint rapidly, is favorable to improve the production efficiency.

Schallamach wave-induced instabilities in a belt-drive system

Abstract: We experimentally study the dynamic behavior of a belt-drive system to explore the effect of loading conditions, driving speed, and system inertia on both the frequency and amplitude of the observed frictional and rotational instabilities. A self-excited oscillation is reported whereby local detachment events in the belt–pulley interface serve as harmonic forcing of the pulley, leading to angular velocity oscillations that grow in time. Both the frictional instabilities and the pulley oscillations depend strongly on operating conditions and system inertia, and differ between the driver and driven pulleys. A larger net torque applied to the pulley generally intensifies Schallamach waves of detachment in the driver case but has little influence on other measured response quantities. Higher driving speeds accelerate the occurrence of frictional instabilities as well as pulley oscillations in both cases. Increasing the system's inertia does not affect the behavior of contact instabilities, but does lead to a steadier rotation of the pulley and more pronounced fluctuations in the belt tension. A simple dynamic model of the belt-drive system demonstrates good agreement with the experimental results and provides strong evidence that frictional instabilities are the primary source of the system's self-oscillation.

Printing device with conveyor belt

Abstract: An inkjet printer, and a printing method with the inkjet printer, includes a first conveyor belt wrapped around a vacuum table and supported by an upstream pulley and a downstream pulley and a vacuum area on the first conveyor belt, and a second conveyor belt wrapped-around the first conveyor belt and supported by an upstream sliding support and a downstream sliding support. The second conveyor belt is adhered in the vacuum area by vacuum power and a print receiver is attached to the second conveyor belt for conveying and printing.

Kinematic chain for transmission of mechanical torques

Abstract: A kinematic chain (100) comprises a first pulley (110), arranged to rotate about a rotation axis x, and a second pulley (120), arranged to rotate about a rotation axis y. The kinematic chain (100) comprises then at least one connecting element (130) comprising at least one passage (131) having at least one rotating element (132), said or each connecting element (130) also comprising at least one interface (135,136) arranged to connect the connecting element (130) to an adjacent connecting element (130) or to a pulley (110,120), generating a rotational constraint about a rotation axis z. The kinematic chain (100) also comprises a transmission element (140) arranged to develop along a determined path for transmitting a rotational motion between the first pulley (110) and the second pulley (120). The transmission element (140) is adapted to be, in use, fixedly in contact with said or each rotating element (132) by a constraint of rolling friction, in order to allow a modelling the determined path according to a predetermined geometry.

Single-Motor-Based Bidirectional Twisted String Actuation With Variable Radius Pulleys

Abstract: In this letter, we proposed a variable radius pulley (VRP) to linearize input-output behavior of twisted string actuators (TSAs). With the help of a VRP, it is possible to make the inherently nonlinear transmission ratio of twisted string constant. This enables design of bidirectional transmission systems driven by a single motor, much like is done in conventional belt transmissions. Herein, we analyze the limitations on employing constant-radius pulleys in bidirectional twisted string transmission systems and propose a VRP design methodology based on TSA kinematics. We manufactured the pulley and evaluated its performance experimentally in a series of unidirectional and bidirectional actuations. The experiments demonstrated that the resultant transmission ratio from motor to load remained nearly constant as expected from the simulation results. Different statistical measures for error between the experimental and simulated results were also calculated.

Dynamics of contour motion of belt drive by means of nonlinear rod approach

Abstract: The contour motion of the belt drive, i.e., the motion with the constant trajectory, is addressed. The belt is considered as a closed Cosserat line whose particles have translational and rotational degrees of freedom. The problem is considered in the framework of geometrically nonlinear formulation with no restrictions on the smallness of displacements and rotations. The spatial (Eulerian) coordinate which is the arc coordinate in the actual configuration is introduced. The belt is divided into four segments: two contact segments on the pulleys and two free spans. The friction forces are assumed to obey the Coulomb law. The study is limited to the stationary case with the constant angular velocities of the pulleys and the equations in components are derived for both contact and free spans. In the contact segment two assumptions are employed to eliminate the unknown contact pressure and friction: (1) the full contact, i.e., coincidence between the pulley and the belt and (2) the stick condition, i.e., the belt velocity is related to the pulley angular velocity. A nondimensional coordinate is introduced in the segments to obtain the boundary value problem with fixed boundaries. The boundary coordinates of the contact zones are the integration constants of the derived problem along with the other constants.

High-Low Pulley Rack System for Weight Machine

Abstract: A pulley rack for an exercise machine includes a support frame, an upright extending generally vertically within the support frame, a counterweight having one or more counterweight pulleys, the counterweight moveable in a vertical direction relative to the support frame, one or more guide pulleys mounted to the support frame, a cable end assembly mounted to the upright, and a pull cable having a fixed attachment end connected to the cable end assembly and a pullable end freely passing through the cable end assembly. The pull cable is routed through the cable end assembly, the counterweight pulleys, and guide pulleys such that a force exerted on the pullable end raises the counterweight. A section of the pull cable extends from the pullable end through the cable end assembly and downwardly to one of the guide pulleys mounted below the cable end assembly.

Dog training device

Abstract: The invention discloses a dog training device. The device includes a seat body, a supporting rod fixed on the seat body, and a rope box fixed on the supporting rod; the rope box is provided with an automatic rolling rope winch; the front end of the supporting rod is provided with a fixed pulley; the free end of a rope goes out of the rope box and winds on the fixed pulley, and the rope section between the fixed pulley and the rope box is provided with a tension sensor; and the tension sensor is electrically connected to a display unit. Thus, problems of police dog explosive force, speed and other police quality training and parameter measurement can be effectively solved, the training efficiency and actual combat effects of police working dogs can be enhanced, and personal danger can be reduced.

Metal parts surface cleaning device for machining

Abstract: The utility model discloses a metal parts surface cleaning device for machining, including the bottom plate, fixed mounting has a support frame on the bottom plate, the vertical fixed mounting in tophas a two screens branch mailbox in the support frame, and screening incasement horizontal slip formula is equipped with left guide arm and right guide rod, the rotation band pulley is gone up to overlap to establish with from the driven pulleys and is connected with driving belt, annular guide way has been seted up to the bottom plate upper surface, and the equal fixed mounting in both ends has to slide to inlay and establishes the direction slider of installing in vertical spout, the vertical expanding spring that is equipped with in vertical spout about the otter board, the utility model discloses a brush plate's the rotation metal parts in to the washing tank rotates the washing, simultaneously brush plate about reciprocating motion enlarged the cleaning range to metal parts, guaranteed the abundant washing of part, the otter board is passed in the upper and lower vibrations of otter board in the cleaning process, the dirt that has promoted the metal parts surface to come off, realizes dirt and metal parts's separation, and it is abundant to rinse more thoroughly.