Parallel Robot Calibration Using Torque-Based End Position Detection
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Solution Overview
Problem
Current calibration methods for parallel kinematic robots are time-consuming, require manual intervention, and are prone to errors, leading to potential mechanical damage and inaccurate positioning.
Innovation Solution
A method involving a movable and adjustable drive connection, such as a length-variable cardan shaft, is used to calibrate and initialize the robot, allowing for program-controlled adjustments of upper arms to precise angular positions using load torque detection and position sensors, enabling automatic centering and positioning without manual intervention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If manual calibration methods are used for parallel kinematic robots, then calibration can be performed with simple equipment, but the process is time-consuming and requires significant staff input
Solution Approach 1:
The calibration system performs automatic self-calibration by detecting mechanical stops through torque sensors and autonomously determining reference positions without requiring manual intervention or external calibration equipment, thereby reducing both calibration time and staff input while maintaining calibration accuracy
Solution Approach 2:
The system replaces manual mechanical calibration operations with an automated control system that uses torque detection and sensor feedback to automatically identify reference positions and perform calibration, eliminating the need for manual staff intervention and significantly reducing calibration time
2Adaptability or versatility
If manual calibration intervention is used, then flexibility in handling various calibration scenarios is maintained, but the process is prone to human errors
Solution Approach 1:
The calibration system continuously monitors torque values during arm movement and automatically detects mechanical stop positions through feedback from torque sensors, enabling accurate and reliable calibration without manual intervention while maintaining the ability to adapt to different calibration scenarios through program-controlled operations
Solution Approach 2:
The system replaces manual calibration operations with an automated control system that uses sensor feedback and programmed logic to perform calibration tasks, eliminating human error while maintaining flexibility through software-controlled adaptability to various calibration requirements
3Productivity
If calibration proceeds without precise positioning control, then the process is simpler and faster, but mechanical damage may occur
Solution Approach 1:
The system uses torque sensors to continuously monitor the mechanical state during calibration and automatically detects when a mechanical stop is reached through torque value feedback, enabling fast yet safe calibration by dynamically adjusting positioning based on real-time torque information without risking mechanical damage
Solution Approach 2:
The system performs preliminary torque detection and mechanical stop identification during the calibration process to establish safe reference positions before proceeding with tool head positioning, ensuring that subsequent movements are constrained within safe boundaries that prevent mechanical damage while maintaining calibration efficiency
4Loss of time
If automatic calibration is implemented, then staff input and time are reduced, but the device complexity increases
Solution Approach 1:
The calibration system achieves automatic self-calibration by utilizing existing torque sensors and control system components already present in the parallel kinematic robot, adding minimal complexity while enabling fast automated calibration without requiring additional specialized calibration equipment or complex external systems
Solution Approach 2:
The calibration system leverages the existing torque sensors and control system of the robot for multiple functions including normal operation monitoring and calibration reference detection, thereby implementing automatic calibration without adding significant device complexity by reusing existing components for dual purposes
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method significantly reduces staff input and time, enhances calibration reliability, and prevents mechanical damage by ensuring precise positioning and alignment of the tool head within the robot's movement range.
Implementation Method 1
adjustment of approximately corresponding angular positions of the at least two upper arms by motor drives by detection of load torques acting on the upper-arm swivel axes
Data Source
AI summary
The invention relates to a method to calibrate a handling device (18) including a handling robot or parallel kinematic robot (24), with a tool head (28) suspended from at least two parallel kinematically movable arms (26). Each of the at least two arms comprises an upper arm, which is movable between two end positions about a defined upper-arm swivel axis (38). Each of the at least two arms also comprises a lower arm (40), which is swivelably mounted on the upper arm. The upper arms are brought into approximately corresponding angular positions by detection of load torques and/or of angle positions. First one, than another of the upper arms is brought into one of the two end positions, and the angular position reached is detected and used for the position initialization or angle initialization of the particular upper arm, whereupon the upper arm is returned.