Articulating Arm Joint Scheduling for High-Strength UGV Lifting
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Solution Overview
Problem
Unmanned Ground Vehicles (UGVs) face challenges in performing high-strength tasks due to power limitations, as they often struggle to lift objects weighing ≥ 50 kilograms, and conventional solutions like adding batteries increase weight and cost or result in slower manipulator movement.
Innovation Solution
Implementing a timeslot-based control method for articulating arm joints, where only a subset of joints are active at a time, using joint brake mechanisms to prevent inactive joints from moving and reduce power draw, allowing the robotic arm to perform high-strength tasks efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If more batteries are added to the UGV, then the power supply capacity is improved, but the weight and volume of the UGV increase
Solution Approach 1:
The system dynamically switches between different operational modes (single-joint mode, multi-joint mode, hybrid mode) based on real-time power availability and task requirements. This allows the UGV to adapt its power consumption characteristics to match available energy resources, eliminating the need for oversized battery systems while maintaining capability to perform high-strength tasks when needed.
Solution Approach 2:
The control system changes operational parameters (which joints are active, movement speeds, task execution timing) based on power conditions. By adjusting these parameters dynamically, the system optimizes power usage without requiring additional battery capacity, thus avoiding increased weight and volume.
2Force
If higher gear ratios are used, then the manipulator strength is improved, but the manipulator movement speed decreases
Solution Approach 1:
The system dynamically selects which joints are active based on the current task requirements and power availability. This allows the manipulator to achieve high strength when needed (by activating specific joints in sequence) while maintaining the ability to move quickly when full strength is not required, effectively decoupling the strength-speed tradeoff that would otherwise require fixed high gear ratios.
Solution Approach 2:
The manipulator control is segmented into independent joint control units, each capable of being activated or deactivated independently. This segmentation allows selective engagement of joints based on instantaneous power availability and task needs, enabling strength amplification without the speed penalty of conventional high gear ratio approaches.
3Productivity
If multiple joints move simultaneously, then the manipulator productivity is improved, but the instantaneous power draw increases
Solution Approach 1:
The system implements periodic activation of different joint subsets across multiple control cycles. Instead of all joints moving simultaneously, joints are activated in staggered sequences (e.g., joint 1 in cycle 1, joint 2 in cycle 2), which distributes power consumption over time while still achieving the overall productive goal of moving the manipulator through its full range of motion.
Solution Approach 2:
The control system dynamically adjusts the number and identity of active joints based on real-time power conditions and task progress. This dynamic adaptation allows the system to maintain productivity by keeping joints active when power is available while reducing instantaneous power draw by limiting active joints when power is constrained.
Data Source
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AI summary
Systems (100) and methods (900) for controlling movement of an articulating arm having a plurality of joints. The methods comprise: receiving, by the controller, a command to perform a task by the articulating arm; ranking movements of the joints based on how much each said joint needs to move at a first time in order to follow the command; selecting a first subset of joints with top-ranked movements from the plurality of joints, where the subset of joints comprises less than a total number of joints contained in the plurality of joints; and causing only the joints of the first subset to move during a first timeslot of a plurality of timeslots.