PID Control with Dual Actuators for Torque Management
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Solution Overview
Problem
Conventional PID controllers in industrial control systems face performance issues due to their reactive nature and the increased workload and maintenance needs when used for both feedback and feedforward control, leading to packaging issues and frequent replacements.
Innovation Solution
Employing a secondary motor dedicated to feedforward control, allowing the primary motor to focus on smaller error corrections, thereby reducing peak torque requirements and enabling easier monitoring and servicing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single actuator is used for both feedback and feedforward control, then device complexity is reduced, but the actuator workload increases leading to larger size requirements and more frequent replacements
Solution Approach 1:
The control function is segmented into two separate actuators: a primary actuator dedicated to feedback control and a secondary actuator dedicated to feedforward control. This segmentation divides the workload, allowing each actuator to be optimized for its specific function and reducing the peak torque requirements for each individual actuator.
Solution Approach 2:
The control system achieves multi-functionality by having the primary actuator handle feedback control while the secondary actuator handles feedforward control. This allows the system to perform both control functions simultaneously with specialized actuators, improving overall system performance without requiring a single oversized actuator.
2Volume of moving object
If a single actuator handles both feedback and feedforward control, then packaging space is reduced, but the actuator size must be larger to handle peak torque requirements
Solution Approach 1:
By segmenting the control functions across two actuators, each actuator can be sized for its specific workload rather than requiring one actuator to handle all peak torque demands. The secondary actuator handles the majority of torque requirements during feedforward operation, allowing the primary actuator to be smaller.
Solution Approach 2:
The secondary actuator performs the excessive action of providing dynamic torque compensation, allowing the primary actuator to operate within its optimal torque range for precision feedback control. This partial specialization reduces the peak torque requirements for each individual actuator.
3Ease of repair
If a single actuator is used for both control modes, then monitoring and maintenance become simpler, but the actuator must be replaced more often due to increased workload
Solution Approach 1:
Segmenting the control functions allows the primary actuator to be monitored specifically for wear during feedback control operations, while the secondary actuator handles the more demanding feedforward control. This separation extends the service life of both actuators by preventing either from being overloaded.
Solution Approach 2:
The secondary actuator provides dynamic torque compensation that compensates for system disturbances and wear, effectively extending the service life of the primary actuator. The system self-regulates to protect the feedback control actuator from excessive stress.
4Stability of the object's composition
If PID loop gains are reduced to prevent overshoot and oscillation, then system stability is improved, but control performance deteriorates
Solution Approach 1:
The secondary actuator performs preliminary action by providing dynamic torque compensation in advance, anticipating system disturbances and payload variations. This allows the primary actuator to use lower PID gains for stability while the secondary actuator pre-compensates for expected disturbances, maintaining both stability and performance.
Solution Approach 2:
The secondary actuator acts as an intermediary that compensates for system disturbances before they affect the primary control loop. This mediator approach allows the primary PID controller to operate with conservative gains for stability while the secondary actuator handles the performance-critical compensation.
Data Source
AI summary
Embodiments of the disclosure provide proportional integral derivative control (PID) using multiple actuators. In one embodiment, a process includes providing a PID controller in communication with a primary actuator and a secondary actuator, the primary actuator and the secondary actuator coupled to a handler, such as a robotic arm for manipulating an object. The process further includes receiving position feedback and a specified trajectory for the handler, and generating a dynamic feedforward force command and a position correction command for the handler based on the position feedback and the specified trajectory. The process further includes providing, from the PID controller, the dynamic feedforward force command to the secondary actuator and the position correction command to the primary actuator.