Robot Impedance Control for Human-Aware Obstacle Response
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Solution Overview
Problem
Existing robots struggle to balance real and perceived safety in unstructured environments with humans, often requiring high real safety measures that compromise efficiency and perceived safety, and vice versa, due to generic obstacle handling that fails to differentiate between humans and inanimate objects.
Innovation Solution
A method using proximity and thermal sensors to distinguish between humans and inanimate objects by adjusting mechanical impedance, reducing it when close to humans to enhance both real and perceived safety, while maintaining efficiency by modifying movement strategies and speed limits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If generic safety actions (sudden stop) are applied to all obstacles, then real safety is improved, but perceived safety deteriorates and productivity decreases
Solution Approach 1:
The robot applies different safety behaviors to different types of obstacles based on their classification. Humans are detected using thermal sensors and treated with smooth deceleration to maintain perceived safety, while inanimate objects trigger sudden stops for maximum real safety. This local differentiation resolves the contradiction by applying appropriate safety measures only where needed.
Solution Approach 2:
The robot dynamically adjusts its safety response based on real-time sensor data and obstacle classification. The control system switches between different safety strategies (smooth deceleration vs. sudden stop) depending on whether a human or inanimate object is detected, allowing the robot to optimize both safety and productivity in different situations.
2Ease of operation
If smooth and speed-limited control is applied to improve perceived safety, then perceived safety is improved, but real safety may be compromised and productivity decreases
Solution Approach 1:
The robot applies smooth, speed-limited control specifically when humans are detected in proximity, while maintaining full speed and sudden stop capability for inanimate objects. This localized application of smooth control ensures perceived safety with humans without compromising real safety or productivity overall.
Solution Approach 2:
The robot uses thermal sensors to continuously monitor for humans and adjusts its control strategy based on this feedback. When a human is detected, the robot switches to smooth deceleration profiles; when no human is present, it returns to aggressive speed profiles, ensuring both perceived and real safety through adaptive feedback control.
3Adaptability or versatility
If thermal sensors and proximity sensors are added to differentiate obstacles, then adaptability is improved, but device complexity increases
Solution Approach 1:
The thermal sensor acts as an intermediary that provides simple temperature-based differentiation between humans and inanimate objects. This single additional sensor type enables sophisticated obstacle classification without requiring complex sensor arrays, resolving the contradiction between adaptability and complexity.
Solution Approach 2:
The robot uses temperature as a simple parameter change to differentiate between human and non-human obstacles. By monitoring temperature thresholds, the system achieves sophisticated obstacle classification using basic sensor data, avoiding the need for complex analysis systems while improving adaptability.
4Reliability
If mechanical impedance is reduced when near humans, then both real and perceived safety are improved, but productivity decreases
Solution Approach 1:
The robot dynamically adjusts its mechanical impedance based on human proximity detection. When humans are detected, the robot reduces impedance for smooth, safe interaction; when no humans are present, the robot maintains high impedance for efficient, fast operation. This dynamic adjustment resolves the contradiction between safety and productivity.
Solution Approach 2:
The robot applies reduced mechanical impedance locally in the direction of human proximity while maintaining normal impedance for other directions. This selective impedance reduction ensures safety with humans without significantly impacting overall productivity, as the robot can still operate efficiently in non-human directions.
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
The method effectively increases real and perceived safety for humans by reducing mechanical impedance and modifying robot movements when near humans, while maintaining efficiency by differentiating obstacle handling, thus improving safety and productivity.
Implementation Method 1
obtaining, by means of a proximity sensor on the robot, a distance value indicative of a distance between an object and the robot
Implementation Method 2
obtaining, by means of a thermal sensor on the robot, a temperature value indicative of a temperature of the object
Data Source
AI summary
A method of controlling a robot, the method including obtaining, by means of a proximity sensor on the robot, a distance value indicative of a distance between an object and the robot; obtaining, by means of a thermal sensor on the robot, a temperature value indicative of a temperature of the object; and controlling the robot to reduce its mechanical impedance if the distance value is smaller than a distance threshold value and the temperature value is higher than a temperature threshold value. A control system for controlling a robot, and a robot including the control system, are also provided.