Control Characteristics of Shape Memory Alloy Actuator Using Resistance Feedback Control Method

2008 ◽  
Vol 59 ◽  
pp. 178-183 ◽  
Author(s):  
Yuji Takeda ◽  
Hiroki Cho ◽  
Takaei Yamamoto ◽  
Toshio Sakuma ◽  
Akihiko Suzuki
Keyword(s):  
Shape Memory ◽  
Position Control ◽  
Control Method ◽  
Current Control ◽  
Input Current ◽  
Arbitrary Position ◽  
Feedback Control Method ◽  
Fine Position ◽  
Control Distance ◽  
Off Time

The actuators using shape memory alloys can work as an actuator to control or retain positioning without using sensor devices. In this work, a position control model with a biasing mechanism is produced. The produced model is controlled by resistance feedback using the method of setting off-time and can be set and retained at an arbitrary position. The effects of input current, control distance and off-time on positioning characteristics such as dynamic behavior and position stability are investigated. The results show that high input current for heating is effective for shortening the rise and settling times. However, the overshoot increases with increasing input current. When the recovery strain is below 2.5%, the rise and settling velocities increase with increasing control distance. Furthermore, the off-time affects position stability. In the case of short off-time, fine position stability is performed regardless of the values of input current and control distance.

Continuous time-varying feedback control of a robotic manipulator with base vibration and load uncertainty

2020 ◽  
pp. 107754632092759
Author(s):  
Xi Wang ◽  
Baolin Hou
Keyword(s):  
Feedback Control ◽  
Lyapunov Function ◽  
Continuous Time ◽  
Position Control ◽  
Control Method ◽  
Robotic Manipulator ◽  
Control Law ◽  
Time Varying ◽  
Load Uncertainty ◽  
Feedback Control Method

To solve precise and fast position control of a robotic manipulator with base vibration and load uncertainty, a continuous time-varying feedback control method based on the implicit Lyapunov function is studied. This method is proportional–derivative-like in the form of control law, but its proportional and differential coefficients depend on the system Lyapunov function, which are differentiable functions of system error variables. In the motion process of the robotic manipulator, the system performance is influenced by three main nonlinear factors: system friction, balance torque, and base vibration. As the former two factors are available to be modeled and identified through experiments, compensation of the two terms is added to the proposed control law to reduce the effects of system nonlinearities to a certain extent. Experimental results show that the proposed control strategy is robust to base vibration and load uncertainty. Besides, the compensation of system friction and balance torque can shorten the positioning time by 27.3%, from 1.32 s to 0.96 s. Meanwhile, the positioning precision is guaranteed, which verifies the effectiveness of the proposed control scheme.

scholarly journals A Novel Control Method and Mathematical Model for Intelligent Robot

2021 ◽  
Vol 15 ◽  
pp. 486-493
Author(s):  
Nianxiang Wu
Keyword(s):  
Steady State ◽  
Dynamic Response ◽  
Position Control ◽  
Control Method ◽  
Current Control ◽  
Robot Dynamics ◽  
Gravity Compensation ◽  
Drive Motor ◽  
Separate Control ◽  
Fast Dynamic

Hamiltonian method based on action micro-control is widely used in the control of mechanical arm synchronous motor. In order to realize the combination of robot dynamics and drive motor control, Hamiltonian control method is used in this paper to exploit a novel controller for robot, which can be used for better steady-state characteristics in the system. However, dynamic response of port-controlled Hamiltonian (PCH) of control system is slower, so the related control method is exploited and coordinated with the proportional-derivative (PD) plus gravity compensation. At this time, the system has both the fast dynamic response of the PD and the steady state of the PCH. The reverse motor method is used and the two controllers are combined by current conversion to realize the overall control of the robot and the drive motor. The robot drive motor is controlled, and the robot joint position control is combined with the drive motor current control by current conversion. It can be seen from the simulation results that the coordinately controlling the end position of robot can reach the desired position quickly and accurately. Moreover, compared with the separate control of PD plus gravity compensation and PCH control method, it is proved that this scheme has both a fast dynamic process and better performance and ability to resist load torque disturbance. So control method proposed in this paper has a good application prospect

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