Robot Force-Torque Control for Impact and Vibration Suppression
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Solution Overview
Problem
Existing robot control technologies cannot effectively suppress impact on persons or objects when robots interact, leading to potential injury or damage due to the lack of force control, resulting in a need for a system that can manage external forces to ensure safe and accurate operations.
Innovation Solution
A control device and method that compares detected external forces from force sensors with estimated forces based on torque data from torque sensors, adjusting torque command values to control robot operations and switch between safety and accuracy modes as needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If position control is used to suppress vibration in the robot, then vibration suppression is improved, but impact suppression on persons or objects is not achieved
Solution Approach 1:
The patent replaces pure position control with a hybrid control system that incorporates force control. The control device calculates external forces from torque sensor data and integrates this with position control commands, substituting the inadequate position-only control mechanism with a combined force-position control mechanism that can suppress both vibration and impact.
Solution Approach 2:
The patent introduces an intermediary force control layer between the position control command and the robot's actual movement. The control device acts as a mediator that processes position commands, adds force control based on external force calculations, and generates corrected torque commands that achieve both vibration suppression and impact suppression.
2Object-affected harmful factors
If force control is added to control the robot's operation, then impact suppression is improved, but control system complexity increases
Solution Approach 1:
The control device performs multiple functions using a unified approach: it processes position control commands, calculates external forces from torque sensor data, corrects torque commands, and outputs controlled movement commands. This multi-functional integration avoids the need for separate complex force control hardware and simplifies the overall system architecture.
Solution Approach 2:
The control device utilizes existing torque sensor data, which was already being collected for other control purposes, and repurposes it for external force calculation and impact suppression. This self-service approach avoids adding dedicated force sensors or separate measurement systems, reducing overall system complexity while achieving force control capabilities.
3Manufacturing precision
If torque command correction is performed based on external force comparison, then operational accuracy is improved, but control processing complexity increases
Solution Approach 1:
The control device performs preliminary calculation of external forces from torque sensor data before generating torque commands. By pre-calculating the external force component and preparing the correction amount in advance, the system achieves accurate torque command correction without increasing real-time processing complexity during critical control moments.
Data Source
AI summary
Provided is a control device capable of controlling the operation of a control target according to a detected external force. A control device (200) includes a control unit (210-1) that compares a first external force detected by a force sensor provided in a control target and a second external force estimated on the basis of a torque detected by a torque sensor provided in an a movable portion of the control target, the movable portion enabling the force sensor to be movable, and controls the operation of the control target by correcting a torque command value on the basis of a result of the comparison.