Gain-Scheduled Position Control of a Pneumatic Muscle Actuator

2021 ◽  
Author(s):  
Matthew Cotton ◽  
Andrew Plummer
Keyword(s):  
Position Control ◽  
Weight Ratio ◽  
Experimental System ◽  
Open Loop ◽  
Tracking Performance ◽  
Precise Position ◽  
Linear Controller ◽  
Highly Nonlinear ◽  
Wide Range ◽  
Gain Scheduled

Abstract Pneumatic artificial muscles (PAMs) are high power-to-weight ratio actuators with considerable potential in biomimetic robotics and orthotics due to their similarities with human skeletal muscle. However, precise position control is difficult to achieve due to the highly nonlinear nature of the actuators and the pneumatic systems driving them. A wide range of nonlinear controllers have been proposed to-date, but none have been shown to be entirely satisfactory, and are often optimised for only one region of the PAM’s travel. In this paper, a gain-scheduled position controller is designed that aims to achieve equal tracking performance across the entire travel of the PAM. Selected scheduling variables include actuator displacement and error direction, with controller gains defined by ‘normalisation curves’ determined by data from open-loop characterisation tests. The experimental system consists of a Festo PAM, a pair of on-off valves driven by pulse-width modulated signals, and sensors for PAM displacement and pressure. Controller performance is tested using several dynamic position tracking tests, and the results are compared to an equivalent linear controller. The gain-scheduled approach successfully counteracts the differing inflation / deflation dynamics of the system, showing improved tracking performance over the linear controller with considerably less variability due to operating region.

scholarly journals The Influence of Valve-Pump Weight Ratios on the Dynamic Response of Leaking Valve-Pump Parallel Control Hydraulic Systems

2018 ◽  
Vol 8 (7) ◽  
pp. 1201 ◽  
Author(s):  
Haigang Ding ◽  
Jiyun Zhao ◽  
Gang Cheng ◽  
Steve Wright ◽  
Yufeng Yao
Keyword(s):  
Dynamic Response ◽  
Hydraulic System ◽  
Weight Ratio ◽  
Open Loop ◽  
Hydraulic Systems ◽  
Variable Speed ◽  
Weight Factors ◽  
Wide Range ◽  
Parallel Control ◽  
Valve Control

A new leaking valve-pump parallel control (LVPC) oil hydraulic system is proposed to improve the performance of dynamic response of present variable speed pump control (VSPC) system, which is an oil hydraulic control system with saving energy. In the LVPC, a control valve is operating at leaking status, together with a variable speed pump, to regulate the system flow of hydraulic oil simultaneously. Therefore, the degree of valve control and pump control can be adjusted by regulating the valve-pump weight ratio. The LVPC system design, mathematical model development, system parameter and control performance analysis are carried out systematically followed by an experimental for validation process. Results have shown that after introducing the valve control, the total leakage coefficient increases significantly over a wide range with the operating point and this further increases damping ratios and reduces the velocity stiffness. As the valve-pump weight ratio determines the flow distribution between the valve and the pump and the weight factors of the valve and/or the pump controls determines the response speed of the LVPC system, thus if the weight factors are constrained properly, the LVPC system will eventually have a large synthetic open-loop gain and it will respond faster than the VSPC system. The LVPC will enrich the control schemes of oil hydraulic system and has potential value in application requiring of fast response.

The Design of Spraying Manipulator Control System in Mines

2014 ◽  
Vol 602-605 ◽  
pp. 1157-1160
Author(s):  
Mei Yu ◽  
Guo Wei Liu ◽  
Bing Kong
Keyword(s):  
Control System ◽  
Position Control ◽  
Low Cost ◽  
Open Loop ◽  
Open Loop Control ◽  
Mining Equipment ◽  
Loop Control ◽  
Precise Position ◽  
Loop Control System ◽  
Manipulator Control

In view of the present mining spraying manipulator operation is not flexible ,spraying effect is poor, susceptible to interference and other issues, this paper studies and realizes a kind of low cost, strong practicability of spraying manipulator control system. Using S7-200PLC and 2MA860H drive to control the 86BYG250A stepper motor open-loop control system, and the precise position control is realized. By controlling of the x-y axis mine spraying manipulator. Validate the system operation is simple, highly efficient and stable, energy conservation and environmental protection, strong anti-jamming capability, it can be widely used in all kinds of mining equipment.

Pneumatic cylinder with magnetorheological brake using serpentine and helix flux guide as a linear hybrid actuator for haptics

2016 ◽  
Vol 28 (10) ◽  
pp. 1303-1321 ◽  
Author(s):  
Max Cinq-Mars ◽  
Hakan Gurocak
Keyword(s):  
Power Efficiency ◽  
Position Control ◽  
Weight Ratio ◽  
Compressed Air ◽  
Pneumatic Cylinder ◽  
Shear Mode ◽  
Precise Position ◽  
Hybrid Actuator ◽  
Pneumatic Cylinders ◽  
Magnetorheological Brakes

This research explored a new linear hybrid actuator, which consists of a pneumatic cylinder with a magnetorheological brake embedded in its piston. Magnetorheological brakes are promising actuators since they can apply large forces in a small actuator size, but they can only oppose motion, as they are passive actuators. Pneumatic cylinders are desirable actuators due to their high force-to-weight ratio and ability to apply active forces. However, they require expensive servo valves for precise position control. The new hybrid actuator benefits from the advantages of magnetorheological brakes and pneumatic cylinders. It can apply forces using compressed air and can resist external forces using the magnetorheological brake. The embedded brake also eliminates the undesirable side effects of using compressed air and allows precise positioning of the piston anywhere in its stroke with simple solenoid valves. Fields such as haptics and robotics might benefit greatly from the use of the hybrid actuator where a high force-to-weight ratio could be employed. The study contributes (1) a triple helix flux guide for the linear magnetorheological brake, (2) serpentine flux path to enable larger braking forces, (3) shear mode activation, and (4) control algorithms that enable use of simple solenoid valves and improved power efficiency. When compared to an existing purely pneumatic control algorithm, the hybrid actuator exceeded the performance in position tracking and force disturbance rejection. A power management algorithm demonstrated that disabling the brake when the piston was in position vastly decreases the power consumption.

scholarly journals Parallel P-PD controller to achieve vibration and position control of a flexible beam

2021 ◽  
Vol 10 (2) ◽  
pp. 149
Author(s):  
Ammar N. Abbas ◽  
Muhammad Asad Irshad
Keyword(s):  
Position Control ◽  
Weight Ratio ◽  
Open Loop ◽  
Flexible Beam ◽  
Beam Model ◽  
Robotic Arms ◽  
Pid Tuning ◽  
Programming Tool ◽  
Control Scheme ◽  
Accurate Position

Robotic arms are considered as a cantilever beam fixed at one end and due to the length-to-weight ratio, it has a significant vibration-induced that needs to be controlled to achieve accurate position, speed control and to increase its efficiency. In this project, a discretized Timoshenko beam model is used to discuss the dynamics of the system. Further, to implement the control on the hardware an experimental setup is fabricated to observe the open-loop and closed-loop responses of the beam made of low-density polyethylene. An accelerometer as a feedback sensor is attached at one end of the flexible beam while another end is fixed at the moving cart having DC motor as an actuator. Simulink is used as the programming tool to perform all of the experimentation. Proportional-integral-derivative (PID) tuning is performed. Following that open-loop responses of the deflection of the beam parallel to the motion are observed with different input waveforms. By applying a proportional control scheme, another experiment is performed to demonstrate the disturbance rejection with an accelerometer as a feedback sensor, while ignoring position control. Finally, a PD and P based parallel control scheme is proposed to obtain simultaneously both position control and vibration reduction.

scholarly journals Taking Sensors Out of Motors

1998 ◽  
Vol 120 (01) ◽  
pp. 74-75
Author(s):  
Greg Paula
Keyword(s):  
Motor Control ◽  
Closed Loop ◽  
Position Control ◽  
Great Accuracy ◽  
Open Loop ◽  
Torque Control ◽  
Disk Drives ◽  
Precise Position ◽  
Speed Regulation ◽  
Signal Processors

This article discusses that advanced signal processors are replacing the feedback sensors that had been required for motor control in applications ranging from disk drives to appliance motors. The traditional method of closed-loop motor control has been to use one or more sensors to provide feedback. A growing number of applications, however, are now eliminating the sensor through one of several methods, such as back electromotive force (EMF) or inductance measurement. Sensorless motors are best suited for applications where speed control is needed, but precise position control is not critical. Sensorless motors are proving to be most appropriate for applications where the position of the rotor does not have to be pinpointed with great accuracy and all that is needed is speed and torque control. Prime candidates for sensorless motors are applications where open-loop scalar control had been used but better speed regulation and more torque at low speed are needed.

scholarly journals Direct tuning of gain-scheduled controller for electro-pneumatic clutch position control

2021 ◽  
Vol 13 (8) ◽  
pp. 168781402110360
Author(s):  
Shuichi Yahagi ◽  
Itsuro Kajiwara
Keyword(s):  
Position Control ◽  
Control Method ◽  
Controller Design ◽  
Design Procedure ◽  
Unknown Coefficient ◽  
Trial And Error ◽  
Highly Nonlinear ◽  
Gain Scheduled Controller ◽  
Gain Scheduled ◽  
Controlled Object

This study proposes a gain-scheduled controller with direct tuning for the position control of a pneumatic clutch actuator that is installed in heavy-duty trucks. Pneumatic clutch actuators are highly nonlinear systems and cannot be easily controlled. Industries require a simple controller design that is easy to understand and requires few trial-and-error calibrations. Therefore, we adopted a gain-scheduled proportional integral derivative (PID) control law, which is a well-known and easy-to-understand nonlinear control method. In this approach, a gain scheduler is expressed using polynomials composed of coefficient parameters and controlled object states. The unknown coefficient parameters of the polynomials are directly tuned from the controlled object input/output data without having to use a controlled object model. The proposed controller design procedure is simple and does not require system identification or trial-and-error tuning. The effectiveness of the proposed method is verified by an experiment using an actual vehicle. The experimental results confirm the effectiveness of the proposed method for the position control of pneumatic clutch actuators.

A high torque to weight ratio robot actuator

Robotica ◽  
1995 ◽  
Vol 13 (2) ◽  
pp. 201-208 ◽  
Author(s):  
James E. Bobrow ◽  
Jayesh Desai
Keyword(s):  
High Speed ◽  
Robot Control ◽  
Position Control ◽  
Weight Ratio ◽  
Experimental System ◽  
Gear Ratio ◽  
Torque Control ◽  
Joint Torque ◽  
Loop Control ◽  
High Torque

SummaryA light-weight, high-torque actuator with accurate torque control capability is described. The actuator uses a small hydrostatic transmission to achieve the advantage of large gear reduction from a high speed DC motor, and retains accurate joint torque sensing and control capabilities with no backlash. A disadvantage of the actuator is that is introduces extra dynamics which must be accounted for in robot control systems. It is shown that state feedback enables closed loop control of joint torque, with full back drivability, through an effective gear ratio of 485:1 for the experimental system. The actuator can therefore be used for both position control and output force control, which is essential for modern robot control algorithms. A mathematical model of the system is presented in this paper along with experimental results.

scholarly journals A new Technique for Position Control of Induction Motor Using Adaptive Inverse Control

2010 ◽  
Vol 6 (2) ◽  
pp. 116-122
Author(s):  
Aamir Ahmed ◽  
Martino Ajangnay ◽  
Shamboul Mohamed ◽  
Matthew Dunnigan
Keyword(s):  
Induction Motor ◽  
Position Control ◽  
Open Loop ◽  
Adaptive Inverse Control ◽  
Loop Control ◽  
Inverse Control ◽  
Control Scheme ◽  
Highly Nonlinear ◽  
Dynamic Performances ◽  
A New Technique

Control of Induction Motor (IM) is well known to be difficult owing to the fact the models of IM are highly nonlinear and time variant. In this paper, to achieve accurate control performance of rotor position control of IM, a new method is proposed by using adaptive inverse control (AIC) technique. In recent years, AIC is a very vivid field because of its advantages. It is quite different from the traditional control. AIC is actually an open loop control scheme and so in the AIC the instability problem cased by feedback control is avoided and the better dynamic performances can also be achieved. The model of IM is identified using adaptive filter as well as the inverse model of the IM, which was used as a controller. The significant of using the inverse of the IM dynamic as a controller is to makes the IM output response to converge to the reference input signal. To validate the performances of the proposed new control scheme, we provided a series of simulation results.

Switching Gain-Scheduled Control Design for Flexible Ball-Screw Drives

2013 ◽  
Vol 136 (1) ◽  
Author(s):  
Masih Hanifzadegan ◽  
Ryozo Nagamune
Keyword(s):  
Operating Conditions ◽  
Tracking Performance ◽  
Ball Screw ◽  
Control Technique ◽  
Tracking Accuracy ◽  
Operating Range ◽  
Screw Drive ◽  
Wide Range ◽  
Ball Screw Drive ◽  
Gain Scheduled

This paper proposes an application of the switching gain-scheduled control technique to the flexible ball-screw drive servo system with a wide range of operating conditions. The wide operating range is caused by the change of the table position and the workpiece mass during the machining operation, and leads to plant dynamics variations. To achieve high tracking performance of the table position against the dynamics variations and the cutting force disturbance, a set of gain-scheduled controllers is designed so that each controller damps out the resonance of the ball-screw system and increases the closed-loop bandwidth for a local operating range, and tracking performance is guaranteed under the switching between these controllers. Experimental results with a laboratory-scale ball-screw drive setup demonstrate that the switching gain-scheduled controller outperforms the nonswitching one by up to 52% in tracking accuracy.

scholarly journals A Fluidic Muscle által kifejtett erő közelítésének vizsgálata MS Excel környezetben

2013 ◽  
Vol 8 (1-2) ◽  
pp. 70-76
Author(s):  
József Sárosi ◽  
Zoltán Fabulya
Keyword(s):  
Weight Ratio ◽  
Artificial Muscle ◽  
High Strength ◽  
Pneumatic Actuators ◽  
Highly Nonlinear ◽  
Wide Range ◽  
Mckibben Muscle ◽  
Air Muscle ◽  
Function Approximations ◽  
Fluidic Muscle

The newest and most promising type of pneumatic actuators is the pneumatic artificial muscle (PAM). Different designs have been developed, but the McKibben muscle is the most popular and is made commercially available by different companies (e. g. Fluidic Muscle manufactured by Festo Company and Shadow Air Muscle manufactured by Shadow Robot Company). Pneumatic artificial muscles have a wide range of use in industrial and medical fields. There are a lot of advantages of these muscles like the high strength, good power-weight ratio, low price, little maintenance needed, great compliance, compactness, inherent safety and usage in rough environments. The main disadvantage is that their dynamic behaviour is highly nonlinear. The most often mentioned characteristic of PAMs is the force as a function of pressure and contraction. In this paper the newest function approximations for the force generated by Fluidic Muscles are investigated in MS Excel.

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