Servo Brakes Research Articles

Application of Finite Control Set–Model Predictive Control for Servo Brake Motion in PMSM Drives

Finite control set-model predictive control (FCS–MPC) has a simple and intuitive optimization procedure. Therefore, FCS–MPC is increasingly being applied to control strategies for electrical drive systems. This article presents a method for servo brake control of a permanent magnet synchronous motor (PMSM) based on FCS–MPC. Accordingly, we propose a reference trajectory introduced in a cost function for brake motions and an alternating procedure with speed control. Moreover, this article clarifies the problem peculiar to servo-brake control using FCS–MPC, i.e., the reduction in tracking performance near the brake position because of the low resolution of the output voltage. In addition to the conventional method, a finite number of smoothed voltages were applied as candidate voltages for FCS–MPC to improve the tracking performance near the brake position. The smoothed voltages can effectively increase the resolution of the output voltage, which results in fewer steady-state errors in angular position tracking during servo brake motion. The simulation and experimental results obtained using a PMSM drive system reveal that the proposed strategy exhibited high performance in tracking the reference target during the operation of servobrakes and the ability to seamlessly alternate between servo brake and motor operations.

Control of planar passive wire-driven support systems using servo brakes

In this research, control of a passive wire-driven system for the physical support of human beings is discussed. The considered support system does not have any active motor and the required force for steering the system is provided by a human operator. In the cases that the handling point deviates from the desired path, the servo brake units apply force and eliminate the position error. Thus, the robot is completely safe in human–robot interaction and can be used for sports training and rehabilitation. In this article, the controllable workspace of the system for tracking some curves is obtained, a controller based on sliding mode is proposed, and a redundancy resolution method is suggested for two applications of the system. The efficiency of the control strategy is investigated by simulating the movement of the robot for each application.

Design and optimization of an electromagnetic servo braking system combining finite element analysis and weight-based multi-objective genetic algorithms

The purpose of this paper is to show the design and optimization of a novel electromagnetic servo brake incorporating an Antilock brake system (ABS) function by Multi-objective genetic algorithms. To consider different design requirements, three types of Axisymmetric Finite element (FE) models were initially formulated parametrically to determine the braking force and position of the pusher at each instant during operation of the proposed device. Using a combination of the FE models and Weight-based multi-objective genetic algorithms (WBMOGA), the optimal geometry and dimensions of the proposed FE models were determined while maximizing the braking force of the device and minimizing both the current supplied by the battery and the weight of the assembly. Once an optimal configuration for each type of servo brake designed had been achieved, three prototypes were built and validated experimentally on a conventional test bench. Finally, the prototype that performed best of the three prototypes was mounted and tested on a hybrid test bench with a realistic ABS device. The good agreement between the results obtained from the simulations and those measured experimentally, suggests that the combination of FE models and WBMOGA may be used successfully to design and optimize any complex electromechanical device.

ワイヤ駆動型パッシブ運動支援システムの制御と経路追従評価

In order to assist human motion in the fields of rehabilitation and sports training, we have developed a passive wire-driven motion support system using servo brakes. For the realization of passive robot system without motors, we controlled the tension of wires by servo brakes and used the constant force spring so that the wire does not loosen. In this paper, we propose a control method in consideration of the influence of wire tension and present path-following experimental results that show more accurate motion can be generated by the control.

Design of an Electromagnetic Servo Brake with ABS Function

The focus of this paper is to show a novel electromagnetic servo brake with ABS function. This electro-mechanical device is designed to be installed in mid-range commercial vehicles, and its operation is performed by the battery of the vehicle itself. A control system based on a linear controller was designed to regulate the electric current used by the servo brake. The device designed was constructed and experimentally validated using a test bench. The good agreement obtained from the experiments suggests that the servo brake with ABS function designed could be used in mid-range commercial vehicles in order to reduce the speed of the wheels while simultaneously preventing the wheels from locking safely.

HMM-based state classification of a user with a walking support system using visual PCA features

The improvement of safety and dependability in systems that physically interact with humans requires investigation with respect to the possible states of the user’s motion and an attempt to recognize these states. In this study, we propose a method for real-time visual state classification of a user with a walking support system. The visual features are extracted using principal component analysis and classification is performed by hidden Markov models, both for real-time fall detection (one-class classification) and real-time state recognition (multi-class classification). The algorithms are used in experiments with a passive-type walker robot called “RT Walker” equipped with servo brakes and a depth sensor (Microsoft Kinect). The experiments are performed with 10 subjects, including an experienced physiotherapist who can imitate the walking pattern of the elderly and people with disabilities. The results of the state classification can be used to improve fall-prevention control algorithms for walking support systems. The proposed method can also be used for other vision-based classification applications, which require real-time abnormality detection or state recognition.

2P1-B14 サーボブレーキを用いた足こぎ車椅子の操舵制御(福祉ロボティクス・メカトロニクス(3))

2P1-B14 サーボブレーキを用いた足こぎ車椅子の操舵制御(福祉ロボティクス・メカトロニクス(3))

Motion Control of Caster-Type Passive Mobile Robot with Servo Brakes

In this paper, we introduce a passive mobile robot called prototype Caster-Type Passive Robot Porter (C-PRP), which is developed on the basis of a concept of passive robotics. This mobile robot consists of two casters with servo brakes and one passive rigid wheel. Prototype C-PRP has passive dynamics with respect to the force applied by a human and controls its appropriate motion with the servo brakes. We derive the feasible braking force/moment applied to the robot on the basis of the characteristics of the servo brakes. This paper especially focuses on a fundamental motion control algorithm based on the feasible braking force/moment. We realize the path tracking function and the collision avoidance function as examples by applying the proposed algorithm to prototype C-PRP. These functions are implemented to prototype C-PRP actually, and experimental results confirm its validity.

2A1-C01 サーボブレーキ制御に基づく双輪キャスタ型パッシブ移動ロボットの運動制御(人間機械協調)

We introduced passive mobile robots consisting of various wheels, omnidirectional wheels or one-wheel casters, which are controlled by servo brakes. These robots employ passive dynamics with respect to the force applied by a human. In this article, we derive and analyze a feasible braking force/moment of each robot that can be applied to the robot on the basis of the characteristics of the servo brakes. We reveal the characteristics, advantages and disadvantages to control, of each robot about the feasible braking force/moment. In addition, we introduce a passive type double wheel caster unit, called PWC, on the basis of the analysis. Finally, we handle a long object by two PWC-P1s actually, and realize the path tracking function as example to confirm its validity.

208202 ブレーキ制御式インテリジェント歩行支援機の開発(OS17 ロボティクス・メカトロニクス3,オーガナイズド・セッション)

208202 ブレーキ制御式インテリジェント歩行支援機の開発(OS17 ロボティクス・メカトロニクス3,オーガナイズド・セッション)

2A1-C02 サーボブレーキ付きワイヤを用いた空間3自由度制御型運動支援システムの開発(人間機械協調)

2A1-C02 サーボブレーキ付きワイヤを用いた空間3自由度制御型運動支援システムの開発(人間機械協調)

J102011 ブレーキ制御式歩行支援システム : 制御方法の実験的検討([J10201]ライフサポート(1))

J102011 ブレーキ制御式歩行支援システム : 制御方法の実験的検討([J10201]ライフサポート(1))

2P2-B07 ブレーキ制御式歩行支援システムの開発 : ブレーキ制御方法の実験的検討(リハビリテーションロボティクス・メカトロニクス)

2P2-B07 ブレーキ制御式歩行支援システムの開発 : ブレーキ制御方法の実験的検討(リハビリテーションロボティクス・メカトロニクス)

2A1-D05 サーボブレーキを用いたワイヤ型運動支援システムの運動制御特性の解析

For supporting human motions, we proposed a motion support system consisting of multiple brake units with wires, and designed a path following function which let human's hands follow to a path by displaying a force. However, the system sometimes cannot generate enough forces to let human's hands follow to the path, because the servo brakes cannot generate driving forces and the system does not have enough brake units to generate desired forces. In this paper, we consider a feasible braking force of the system with multiple brake units theoretically and discuss the numbers of brake units for generating the desired force. We also develop a system based on the proposed theory and conduct the path following experiments. The experimental results illustrate the validity of the proposed theory and system.

Transporting an Object by a Passive Mobile Robot with Servo Brakes in Cooperation with a Human

In this paper, we introduce a passive mobile robot called PRP (Passive Robot Porter) to realize transportation of an object in cooperation with human, which is developed based on a concept of passive robotics. PRP consists of three omni-directional wheels with servo brakes and a controller. It can manipulate an object by controlling an external force/moment applied by a human based on the control of the servo brakes. We consider the characteristics of the servo brakes and control the brake torque of each wheel based on the brake force/moment constraint so that several motion functions of PRP are realized based on the applied force. This allows PRP to track a path which includes motion perpendicular to the pushing direction of the human without using servo motors. The impedance-based motion control is also realized with respect to the perpendicular to the pushing direction. These functions are implemented on PRP experimentally, and the experimental results illustrate the validity of PRP and its control method.

1A2-D18 サーボブレーキを用いたパッシブ型ダンスパートナロボットの協調運動制御

In this research, we develop a Passive Dance partner Robot (PDR) for realizing the effective human-robot cooperation. Different from the active-type robot with servo motors, passive robot is controlled by the servo brakes attached to the wheels of the robot and its driving force is the actual force/moment applied by a human. In this paper, we propose a motion control algorithm of the PDR for realizing the ballroom dance with a male dancer based on the estimation of the next dance step intended by him.

Motion Control of Passive Intelligent Walker Using Servo Brakes

We propose a new intelligent walker based on passive robotics that assists the elderly, handicapped people, and the blind who have difficulty in walking. We developed a prototype of the robot technology walker (RT walker), a passive intelligent walker that uses servo brakes. The RT walker consists of a support frame, two casters, two wheels equipped with servo brakes, and it has passive dynamics that change with respect to applied force/moment. This system is intrinsically safe for humans, as it cannot move unintentionally, i.e., it has no driving actuators. In addition, the RT walker provides a number of navigational features, including good maneuverability, by appropriately controlling the torque of servo brakes based on RT. We propose a human adaptive motion control algorithm that changes the apparent dynamics to adapt to user difficulties, and an environmentally adaptive motion control algorithm, which incorporates environmental information to provide obstacle/step avoidance and gravity compensation functions. The proposed control algorithms are experimentally applied to the RT walker to test their validity.

2P1-I04 人間の操作力減少を考慮したパッシブ型移動ロボットのための物体協調搬送制御(作業移動ロボット・メカトロニクス)

In this paper, we introduce a passive type mobile robot referred to as "PRP" to realize a transportation of an object in cooperation with a human based on a concept of passive robotics. PRP consists of support frame, three onmi-directional wheels with servo brakes (MR Brakes) and a controller. It can manipulate an object by controlling the external force/moment applied by human based on the control of the servo brakes. In this case, when the required external force/moment becomes large, tue transportation can be out of control. To overcome this problem, we propose a system in which the PRP grabs an object by using a Free .Joint so that compared to the previous version of PRP, t;he human operator can transport the object without considering the orientation of the robot, and the required intentional force for transporting the object could be reduced, Addlitionally, in this paper, we propose motion control algorithm for this system and we illustrate the decrease of handling force which is needed for transportation by using this algorithm.

Wheel Speed Servo Brake Based on Discrete Sliding Mode Control for Railway Vehicles

Recently, the studies about wheel slip control based on sliding mode control theory were developed and reported. The proposed controllers based on sliding mode control were effective for wheel slip control against railway vehicles. However, those were considered as continuous-time system, and not designed the discrete time system. This paper will present the experimental results about the new wheel slip control, designed by the discrete sliding mode control. The experiments for the proposed wheel slip control are performed while comparing a continuous-time system sliding mode controller. The experimental results proved the effectiveness of the proposed control as compared with a continuous-time system sliding mode, and showed the high brake performance under the nonlinear characteristics of brake dynamics.

パッシブロボティクス概念に基づいた知的歩行支援機の開発

In this paper, we propose a concept of Passive Robotics which is one of the approaches for supporting humans physically. Based on the passive robotics, we develop a new intelligent walker referred to as RT Walker for supporting elderly people, blind people, or handicapped people who have difficulties in walking. RT Walker consists of a support frame, wheels, servo brakes, and controllers. RT Walker has a passive dynamics with respect to a force/moment applied to it and a simple structure, because it does not have some servo motors. However, several functions for RT Walker could be realized by controlling the brake torque of each servo brake appropriately based on Robot Technologies (RT) . In this paper, especially, we propose motion control algorithms of RT Walker for changing its apparent dynamics to adapt to difficulties of the user, and for moving based on the information of an environment. The proposed control algorithms are implemented in RT Walker actually, and the experimental results illustrate the validity of RT Walker and its motion control algorithms.