Mobile Manipulator Dynamic Mass Estimation During Payload Motion
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Solution Overview
Problem
Conventional mobile manipulator robots are loosely integrated, leading to inefficient and inflexible operation in warehouse and logistics environments, as they struggle to perform complex and dynamic motions due to suboptimal coordination between the manipulator and the mobile base.
Innovation Solution
A highly integrated mobile manipulator robot with system-level mechanical design and holistic control strategies between the manipulator and the mobile base, combined with dynamic mass estimation methods that allow for the estimation of payload mass characteristics while the payload is in motion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional loosely integrated mobile manipulator robots are used, then device simplicity is maintained, but operational efficiency and coordination between manipulator and mobile base deteriorate
Solution Approach 1:
The patent merges the mobile base and manipulator into a highly integrated system where the manipulator is physically coupled to the mobile base, enabling coordinated motion planning and control. This integration allows the system to perform complex tasks that require synchronized movement of both base and manipulator, significantly improving operational efficiency compared to loosely coupled systems.
Solution Approach 2:
The integrated mobile manipulator system is designed to perform multiple functions including autonomous navigation, payload manipulation, and dynamic mass estimation. The system can adapt to different task requirements by coordinating the mobile base and manipulator in various ways, making it a versatile platform for warehouse and logistics applications.
2Loss of time
If dynamic mass estimation is performed while payload is in motion, then real-time operational adjustment is enabled, but measurement precision may deteriorate due to motion-induced vibrations and accelerations
Solution Approach 1:
The system performs mass estimation dynamically while the payload is in motion, rather than requiring the payload to be stationary. The control system executes excitation routines that intentionally move the payload through specific trajectories, allowing mass characteristics to be estimated during operational tasks. This eliminates the need for separate calibration time while providing real-time mass information for operational adjustment.
Solution Approach 2:
The system uses force sensors and motion data from the mobile base and manipulator to continuously estimate payload mass characteristics. This feedback mechanism allows the system to monitor and adjust for mass variations in real-time, maintaining measurement accuracy despite motion-induced disturbances by continuously updating the mass model based on observed dynamics.
3Measurement precision
If excitation routines are used to determine accelerations for mass estimation, then measurement capability is improved, but operational time increases
Solution Approach 1:
The system performs mass estimation continuously during normal operational tasks rather than requiring dedicated measurement time. The excitation routines are integrated into the payload manipulation tasks, allowing the system to gather mass estimation data while performing useful work. This eliminates idle measurement time and maintains continuous productivity.
Solution Approach 2:
The system uses partial excitation routines that apply minimal intentional motion beyond what is required for the primary task. Rather than executing full-scale oscillation routines that would significantly extend task duration, the system uses small perturbations and natural task-induced motions to gather sufficient data for accurate mass estimation, thereby minimizing the impact on operational time.
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
Enables the robot to perform complex and dynamic motions, improving speed, agility, and efficiency in warehouse and logistics tasks, while allowing for real-time adjustment of operations based on estimated payload mass properties.
Implementation Method 1
sensing the wrench using a 6-axis force/torque sensor
Implementation Method 2
determining one or more accelerations of the payload based, at least in part, on one or more motions of the robot
Data Source
AI summary
A method of estimating one or more mass characteristics of a payload manipulated by a robot includes moving the payload using the robot, determining one or more accelerations of the payload while the payload is in motion, sensing, using one or more sensors of the robot, a wrench applied to the payload while the payload is in motion, and estimating the one or more mass characteristics of the payload based, at least in part, on the determined accelerations and the sensed wrench.