Showing papers on "Dynamic braking published in 1989"

Adaptive controller for regenerative and friction braking system

Abstract: A regenerative and friction braking system for a vehicle having one or more roadwheels (20,22) driven by an electric traction motor (12) includes a driver responsive device for producing a brake demand signal having a magnitude corresponding to the level of braking force selected by the driver and friction and regenerative brakes operatively connected with the roadwheels of the vehicle A system according to this invention further includes control means (30) for operating the friction and regenerative braking subsystems so that maximum brake torques sustainable by the roadwheels of the vehicle without skidding or slipping will not be exceeded

Antilock braking system with device for delaying yaw - evaluates difference between braking pressures at wheels on one axle and imposes pulsatile braking where needed

Abstract: The brake valve (1) operated from the brake pedal (2) supplies fluid pressure from a source (3) to left- and right-hand side braking pressure control valves (4a,4b) for respective wheels (5a,5b). Signals from wheel speed sensors and comparators (8a,8b) of actual and desired pressures (9a,9b) are forwarded to a processor (6). A yaw build-up delay device therein prevents excessive braking where the adhesion is poorer, and also provides for synchronised pulsation of the braking pressure at both wheels. ADVANTAGE - Controllability and ride comfort of vehicle enhanced even in conditions of unequal adhesion coeffts. at different wheels.

Pressure-generating device for braking circuits of motor vehicles

Abstract: Pressure-generating device for braking circuits of motor vehicles of the type having electric motors for controlling a device for generating braking pressure. Electric motors (15), associated with each wheel (1, 1', 2, 2') or pair of wheels (1,1'-2,2') of the same axle, drive positive displacement pumps (16) generating the braking pressure for cylinders (7) of brakes (3 to 6).

Braking device for elevator winding machine and elevator using the braking device

Abstract: A braking device for an elevator winding machine generates a braking force by contacting a rotary body driven by a rotary shaft of the winding machine with a brake section supported through the intermediary of an elastic body. The elastic body has a nonlinear elastic characteristic so that a starting shock to the passengers in the elevator car is prevented and the braking torque detecting accuracy is improved.

Process and arrangement for constant speedkeeping through actuation of a motor vehicle's braking system

Abstract: The invention relates to a process and arrangement designed, through braking, to keep constant the speed of a motor-vehicle when travelling on downhill slopes. With the aim of producing simple actuation and deactuation of the constant speedkeeping function, the invention is characterized principally in that the constant speedkeeping function commences upon actuation of a driver-activated brake control (17). In connection with this, the lowest vehicle speed is stored as a target value within the memory of a control unit (1). The actual vehicle speed is then regulated towards the target value through activation of the vehicle brakes (4). Only once an ordinary driver-activated control (19) is activated, is the specified regulation towards the target value suspended.

Process for carrying out a load-dependent brake regulation of brakes on a vehicle having an anti-lock system

Abstract: A process for load dependent braking regulations (ALB) utilizing components, signal paths and transmitters of an existing anti-lock braking system (ABS) to perform an automatically load-dependent braking function which takes effect well below the locking limit. The brake pressure and consequently the brake distribution are controlled by processing only wheel-speed differences as actual values of an electronic brake-pressure controller instead of absolute wheel slips. To compensate for changing load situations and roadway properties, the precontrollable brake-force distribution and the brake-pressure level control triggerable at the pedal are corrected in a self-learning and adaptive manner. The device for carrying out the ALB process consists essentially of a computer and software program using input from the ABS systems. The process according to the invention makes axle-load sensors superfluous.

Braking force measurement for motor vehicle wheels - using parameter estimation method with measured valves of wheel speed and braking pressure

Abstract: The braking forces of the wheels of a motor vehicle are determined from the measured values of wheel speed and braking pressure by the use of a parameter estimation method. The dynamict wheel load is determined from the measured value of the coefficient of friction and the braking force. The method can be applied in braking force control systems, e.g. in anti-lock braking systems. It can be applied to each individual wheel of the vehicle irrespective of whether it is a driven or free wheel. USE/ADVANTAGE - For use in determining braking forces and dynamic wheel loading of wheels of braked motor vehicle. Involves use of simple and efficient alogorithms and is suitable for implementation on microprocessor.

Dynamic braking apparatus for a motor

Abstract: A control apparatus for a motor including m number of stator windings and a relay having m-1 contacts, thereby allowing the control apparatus to be simplified in its structure so that the control apparatus can be constructed at a low cost.

Procedure and device for controlling the brake installation of heavy vehicles

Abstract: These provide for continuous measurement of parameters characterising the state of the vehicle, such as the speed of the vehicle, the inclination of the roadway, the axle load and the lateral acceleration. Furthermore, the braking capability is continuously monitored, for which purpose the temperature of the brakes, their state of wear, the state of a pneumatic reservoir and the tyre pressure are measured. It is determined for a given state of vehicle and brakes whether the braking distance to be anticipated is longer than a predetermined reference braking distance. If so, the driver is warned and/or a reduction of the vehicle's speed forcibly initiated.

Controller for electric clamp

Abstract: A controller (21) for an electric clamp (1) closes the clamp rapidly at first, then runs at a slower speed while contacting the workpiece, and speeds up again after contacting it, to close with full clamping force. Arrival of the clamp at the position for slowing down is directly detected by means of a proximity sensor (41), as are arrivals at other positions (39,43). The speed of operation is relatively insensitive to the voltage of its AC electrical power source because an open-loop compensating signal (111,113,715) controls the pulse duration of rectified DC pulses that drive the motor. The controller has dynamic braking (101,105) that is applied between individual pulses of pulse trains of motor current; this results in significant increase in swings of current values for a given motor speed, that reduces harmful effects of mechanical friction. Two jogging speeds are selectable (167).

Three-channel adaptive braking system

Abstract: An adaptive braking system (10, 210) for an automotive vehicle provides a three-channel split pump-back system which may be utilized with either two- or three-chamber master cylinders. The three-channel adaptive braking system (10, 210) includes a first braking circuit (40) for controlling one of the front wheel brakes (25), a second braking circuit (60) for controlling the other of the front wheel brakes (27), and a third braking circuit (80) for controlling the rear wheel brakes (24). A two-section pump (110) provides hydraulic pressure for the first and second braking circuits (40, 60) and for the third braking circuit (80). Alternatively, a three-section pump (310) can provide hydraulic pressure for each of the circuits (40, 60, 80).

Braking system for electric railcars including means for controlling electric brake force

Abstract: A braking system for an electric railcar having an a.c. motor with a variable voltage variable frequency inverter. The inverter controls the voltage and frequency supplied to the a.c. motor in response to the railcar speed, commands from the cab, load conditions, etc. The braking system also includes a pneumatic brake which operates at low speeds. A control circuit operates the inverter to supply electric braking down to a slow speed and then simultaneously applies electric braking and pneumatic braking, smoothly increasing the pneumatic braking force until the railcar stops. During the transistion from electric braking to pneumatic braking the control circuit maintains an output frequency from the inverter to the a.c. motor in the vicinity of 0 Hz, keeping the voltages in the positive phase range.

Dynamic braking device for motor

Abstract: PURPOSE:To reduce a cost and to provide an explosion-proof property by connecting a rectifiers circuit to each of a plurality of motors, and connecting their outputs to a common energy consuming means. CONSTITUTION:A motor drive circuit for control and drive of a plurality of servo motors 21-23, such as of a robot is stopped at the time of power interruption, and the drive controls are execute by inverters 24-26. This driver circuit is composed of diodes 40-48, an energy consuming resistor 49, a field effect transistor 50, a Zener diode 51, a photocoupler 56, etc. A DB operation stop signal becomes OFF by an inverter operation stop signal from a controller 57 at the time of power interruption, the motors 21-23 are rotated by the inertia of load 58 to generate counterelectromotive forces. The voltages are rectified by 3-phase full wave rectifiers formed of the diodes 40-48, consumed by the resistor 49, thereby dynamically braking the motors 21-23.

Apparatus for controlled braking of driven yarn engaging rolls

Abstract: In a textile draw warping system having independently driven sets of draw rolls (28, 30, 32, 34; 36, 38, 40) and an independently driven warp beam (62), synchronous braking of the driven components is controlled by individual pneumatic brakes (74) at each driven component operated by a central programmable logic control system (76) to brake the driven components at respective rates of deceleration preset to maintain constant speed ratios between the driven components during braking. Auxiliary control of dynamic braking and driving of the several drive motors (50, 58, 64) corrects deviations in the driven components' predetermined rates of deceleration.

Braking system and break-away braking system

Abstract: The present invention provides an electric braking system and an electric break-away braking system which provide sufficient power, i.e. both current and voltage, to all the electric brakes of a truck or trailer to fully activate them when braking is required. Both braking systems of the present invention utilize two voltage sources which are normally connected in parallel for charging. When braking is required, however, the electronic control circuitry switches the voltage sources from a parallel configuration into a series configuration to provide a sufficient voltage to overcome the resistance losses in the brake lines and thereby provides enough voltage at the electric trailer brakes to have them provide the maximum possible braking.

Braking performance and stability of motorcycles with and without anti lock braking systems

Abstract: Brake force distribution to the front and rear wheel is normally left to the riders of motorcycles; some production vehicles have so called combined or integrated brakes where brake force distribution is predetermined by design. Research work on the braking behaviour of motorcycles was done with two 1000 cc motorcycles, which were equipped with two different ABS (mechanical/ electronic) and subjected to driving experiments on various road surfaces at different speeds in straight ahead and curve braking. Braking performance and driving stability was investigated for normal and emergency braking with both standard and combined brakes with and without ABS. The results demonstrate, that braking performance and safety is best with ABS in a combined brake vehicle. Curve braking is difficult and complex in any case and needs more research which is in progress in Darmstadt right now (A).

Heavy duty vehicle dynamics related to braking, steering and tyres - swedish research and proposals by vti

Abstract: Research concerning heavy duty vehicle dynamics related to braking, steering and tyres has been conducted by the Swedish Road and Traffic Research Institute (VTI) for about 20 years. The aim has been to develop test procedures and propose minimum performance requirements primarily for vehicle combinations. This paper summarizes results concerning dynamic stability in a double lane change manouevre at constant speed, overturning stability, emergency antilock braking performance under winter conditions in terms of stability, steerability and braking performance during emergency braking in a turn on ice and druing straight line braking on ice, split friction and transition from low to high friction. Hybrid simulation and a tyre tester are also described. (A) For the covering abstract of the conference see IRRD 860578.

Emergency compressed-air brake for automobiles

Abstract: An emergency compressed-air brake for automobiles has the advantage to combine integrally the emergency braking, the service braking and the parking braking, which can be widely used in various road vehicles. The combined braking air-chamber involved is simple in construction. The thrust of braking includes two parts, the air pressure thrust and the spring thrust, with the resultant force of the two thrusts as a service braking thrust, with the spring thrust as a parking and emergency braking thrust. Since the spring force throughout joins in the braking, the braking gets more smoothness and is able to anti-locking.

Dual mode locomotive

Abstract: A description is given of the FL9/AC dual-mode locomotive developed for operation on the Metro-North Commuter Railroad. The locomotive (a modified FL9) was remanufactured to have: gate-turn-off (GTO) thyristor technology instead of silicon-controlled rectifiers; a 12-cylinder turbocharged engine; a single electrically driven air compressor; a blended dynamic brake; provision for regenerative braking; a new cab signal system; and an improved air-brake system. Equipment selection for the FL9 is described and details of construction are presented. >

Controlling method for four-wheel steering device

Abstract: PURPOSE:To prevent hunting due to inertia of a motor, in a motor driving device which performs PWM control, by forming a circuit which shortcircuits its motor while a PWM signal during the PWM control is off so as to afford braking force to a motor. CONSTITUTION:In a motor driving device fit for an electric power steering device and the like, a general H bridge circuit for controlling its motor has respective transistors Tr 1, 3 and 2, 4 in the lower and upper sides thereof and a motor 5. In this case, Tr 2 is a made to be on during the period when the Tr 1 is off, while the Tr 4 is made to be constantly on as usual. Regenerative electric current is thereby guided to pass through the motor 5 during the period when the Tzr 1 is off, then dynamic braking electric current is guided to pass therethrough to make it possible to brake the motor 5. Respective signals sent to the gate terminals TM 1-TM 4 of the Tr 1-Tr 4 are generated from a logic circuit or a microcomputer.

Anti-lock brake control method

Abstract: In a method of anti-lock brake control, in which when the wheel is about to become locked, a control valve is capable of controlling a braking pressure for a brake device irrespective of a braking operation. The control valve is operated to reduce the braking pressure of the brake device in order to reduce a braking force, thereby preventing the wheel from becoming locked. When the braking pressure is to be recovered, the control valve is operated to intermittently increase the braking pressure of the brake device for a given time in order to moderate the increasing of the braking force. The control of the intermittent increasing of the braking pressure is stopped when the completion of the braking operation has been detected in the course of intermittently increasing the braking pressure in recovering the braking pressure. This avoids the wasteful operation of the control valve to prevent the generation of any unwanted operational noise and a wasteful consumption of electric power.

Magnetic disc driver

Abstract: PURPOSE:To speed up dynamic braking by inserting a voltage drop means into the relay part of a dynamic braking circuit juxtaposed with a power switch part. CONSTITUTION:In a magnetic disc driver, a spindle motor 1 is connected with a power switch part 2 via the contact part 32 of a relay part 3a and said switch part 2 is provided between power source part Vcc and earth part GND. Also, said relay part 3 constitutes the dynamic braking circuit of said motor 1. In this case, a voltage drop means 5 by one diode is connected with a coil part 31. When the power source part Vcc is broken, a source voltage value lowers and the number of revolutions of the motor 1 begins to lower at the same time. Then, when said value is equal to the forward voltage value in said diode 5, said coil part 31 of the relay part 3 is no longer excited and the counter- electromotive force of said motor 1 is short-circuited between a-c of the contact part 32. As a result, the motor 1 is brought to the dynamic braking state and its number of revolutions decreases abruptly.

A control system for maintaining constant braking torque on a disk brake dynamometer

Abstract: Most manufacturers of composite friction materials do not possess adequate facilities to test their products dynamically. A practical solution is to simulate the braking process in the laboratory mechanically by means of a disc brake dynamometer. The authors describe a control-system design for the dynamometer. The function of the control system is to maintain a constant braking torque for the testing of brake blocks. A constant braking torque is necessary to create a realistic simulation of the true situation. A driver of a motor car continually varies the force exerted on the brake pedal while braking in order to maintain a constant deceleration of his vehicle. In this case, the driver is the controller who subconsciously adjusts the force on the brake pedal to compensate for the natural variations in the value of the friction coefficient of the brake block material. Therefore, by controlling the dynamometer's breaking torque, it is possible to determine the dynamic change in the friction coefficient of the material under test. After describing the control system philosophy and the design criteria, the authors discuss the pressure controller in detail. >

Dynamic braking without specialized controls

Abstract: The author reviews existing braking methods and compares the alternative methods for braking motors used in the textile industry. He discusses the use of three types of internal braking to increase productivity and product quality. They are plug stopping, and DC electronic braking, and microcomputer-based braking. Microcomputer-based braking has been added to the application engineers tools for torque control of motors. The microprocessor-based braking with automatic shutoff can reduce setup time while minimizing the heat generated by motors. This is especially true when the load varies. Fewer components result in faster installation, and with automatic shutoff the stopping time is not constrained by internal timers with fixed maximum time. >