Robot Manipulator Force-Feedback Safety Mode for Collision Control
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Solution Overview
Problem
Current methods for controlling robot manipulators do not adequately reduce the risk of injury or damage when collisions occur, particularly with human beings, as they lack effective mechanisms to adjust movement speed and direction based on real-time force feedback and medical parameters.
Innovation Solution
A method and device that utilize a sensor to record a force-time profile, activating a safety mode if specific conditions are met, allowing for speed or torque control adjustments based on medical parameters to prevent injury, and implementing a force control mechanism to regulate movement in response to detected forces, thereby reducing the risk of damage during collisions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If speed or torque control is used before safety mode activation, then productivity is maintained, but safety and injury prevention deteriorate
Solution Approach 1:
The control system dynamically switches between speed/torque control and force control based on real-time collision detection. Before collision, speed control maintains productivity; after collision detection (when force exceeds threshold), the system transitions to force control to prevent injury, making the control mode adaptive rather than static
Solution Approach 2:
The system continuously monitors external forces acting on the manipulator and uses this feedback to determine when to activate safety mode. The force sensor provides real-time feedback about collision conditions, enabling the control system to respond appropriately by switching control modes based on actual environmental interaction
2Object-affected harmful factors
If force control is implemented to prevent injury, then safety improves, but productivity deteriorates due to movement restrictions
Solution Approach 1:
The system dynamically adjusts control stiffness based on collision severity. During normal operation, speed control provides full productivity; during collision, force control with adjustable stiffness parameters allows the manipulator to yield appropriately to human presence while maintaining task continuity when safe
Solution Approach 2:
The force control mode uses adjustable stiffness parameters that can be modified based on the detected collision situation. By changing these control parameters dynamically, the system can balance safety requirements with productivity needs depending on the severity and context of the collision
3Object-affected harmful factors
If collision detection sensitivity is increased to detect all potential injuries, then safety improves, but false alarms increase reducing operational efficiency
Solution Approach 1:
The system uses adjustable force thresholds that can be tuned to differentiate between normal operational forces and potentially harmful collisions. By optimizing these threshold parameters, the system achieves sensitive collision detection while minimizing false alarms that would disrupt normal operations
Data Source
Figure 1
AI summary
The invention relates to a device and a method for the open-loop / closed-loop control of a robot manipulator (202) which comprises a sensor (203) for detecting an interaction with an environment. The method according to the invention is characterized in that the sensor (203) detects a force-time curve of an external force (I) acting upon the robot manipulator (202). If the value of the detected force (II) is higher than a defined threshold value G1: (II) > G1, a safety mode of the robot manipulator (202) is activated and controls a movement speed (III) and/or a movement direction (IV) depending on the detected force (I), the movement speed (III) and/or the movement direction (IV) of the robot manipulator (202) being regulated by an open-loop / closed-loop control depending on predetermined medical injury parameters before the safety mode is activated.