Robot Torque and Force Sensor Configuration for Contact Detection
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Solution Overview
Problem
Conventional robots equipped with single-axis torque sensors and six-axis force sensors struggle to detect contact conditions accurately, especially when torque does not act on the torque sensors, leading to missed detections and increased complexity and cost.
Innovation Solution
A robot design incorporating three single-axis torque sensors and a single force sensor capable of detecting force in multiple directions, allowing for comprehensive contact detection without relying on the operation angle of the rotary barrel, thereby reducing sensor count and cost while enhancing detection capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple six-axis force sensors are installed to detect all contact conditions, then detection accuracy is improved, but device complexity and cost increase
Solution Approach 1:
The patent divides the detection function into two specialized components: single-axis torque sensors for detecting torque around parallel axes, and three-axis force sensors for detecting forces in directions intersecting the axes. This segmentation allows each sensor type to be optimized for its specific function, reducing the need for multiple six-axis sensors while maintaining comprehensive detection capability.
Solution Approach 2:
The combination of single-axis torque sensors and three-axis force sensors creates a multi-functional detection system. The torque sensors handle rotational torque detection around parallel axes, while the force sensors handle linear force detection in intersecting directions, together providing comprehensive contact condition detection that would otherwise require multiple six-axis sensors.
2Measurement precision
If six-axis force sensors are used to detect all forces and torques, then comprehensive detection is achieved, but cost increases
Solution Approach 1:
The patent segments the detection system into specialized single-axis torque sensors and three-axis force sensors, replacing the need for multiple six-axis sensors. This segmentation allows using simpler, more cost-effective sensor types for specific detection tasks while maintaining comprehensive detection coverage.
Solution Approach 2:
Instead of using expensive six-axis sensors for all detection tasks, the patent uses a combination of simpler single-axis torque sensors and three-axis force sensors that together replicate the comprehensive detection capability of multiple six-axis sensors, reducing overall system cost.
3Ease of manufacture
If torque sensors are positioned to detect torque around parallel axes, then torque detection is simplified, but forces orthogonal to the axes cannot be detected
Solution Approach 1:
The patent segments the detection functions by placing single-axis torque sensors for torque detection around parallel axes, and separately positioning three-axis force sensors to detect forces in directions intersecting those axes. This segmentation ensures each sensor type operates in its optimal configuration while together they provide comprehensive detection.
Solution Approach 2:
The three-axis force sensor acts as an intermediary that detects forces orthogonal to the torque sensor axes. While torque sensors handle rotational torque around parallel axes, the force sensor mediates the detection of linear forces in intersecting directions, filling the detection gap without requiring complex reconfiguration of the torque sensors.
Data Source
AI summary
A robot includes: a first member; a second member that is rotationally driven around a first axis with respect to the first member; a third member that is rotationally driven around a second axis with respect to the second member, the second axis being located at an interval from the first axis; a single axis torque detection unit that detects only at least one of torque around the first axis and torque around the second axis; and a force sensor that is provided between the first member and a surface to be installed, or in the first member, the second member or the third member, and is capable of detecting force in a direction intersecting with both the first axis and the second axis.