Self-Balancing Vehicle Control Using CMGs and Roll Angle Calculation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional control methods for two-wheeled self-balancing vehicles are insufficient due to the complexity of forces involved, which requires more sophisticated sensing and control systems compared to rocket guidance calculations.
Innovation Solution
The implementation of an IMU, control moment gyroscopes (CMGs), and an accelerometer to measure y-axis acceleration, allowing for the calculation of roll angle and generation of CMG commands to counteract centrifugal and gravitational forces, with steering augmentation to reduce CMG load and provide backup control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional control methods (rocket guidance calculations) are applied to two-wheeled vehicle control, then the control system can be kept relatively simple, but the control precision and stability are insufficient due to the complexity of forces involved
Solution Approach 1:
The control system is segmented into distinct functional modules: IMU for sensing, CMGs for actuation, and separate control algorithms for different force components (centrifugal force, gravitational force, tire slip detection). This segmentation allows each module to be optimized independently while maintaining overall system precision without excessive complexity.
Solution Approach 2:
Control Moment Gyroscopes (CMGs) serve as intermediary actuators between the control system and the vehicle dynamics. The CMGs provide precise torque control to counteract complex forces (centrifugal, gravitational) without requiring direct mechanical intervention, thereby achieving high control precision while maintaining manageable system complexity.
2Reliability
If CMGs are used to counteract centrifugal and gravitational forces, then balance control precision is improved, but the CMG load and compensation requirements increase
Solution Approach 1:
The control system performs preliminary detection of tire slippage and anticipates centrifugal and gravitational forces using IMU data and steering rate measurements. By detecting these conditions early and pre-calculating required compensations, the system reduces the reactive CMG load and energy requirements while maintaining reliable balance control.
Solution Approach 2:
The system continuously monitors vehicle state (roll angle, steering rate, acceleration) and uses this feedback to dynamically adjust CMG commands. This closed-loop feedback ensures that CMGs only provide necessary compensation, optimizing energy usage while maintaining high reliability in balance control during aggressive maneuvers.
3Use of energy by moving object
If steering augmentation is implemented to reduce CMG load, then energy efficiency is improved, but the control system complexity increases
Solution Approach 1:
The IMU and processing element serve multiple functions: they detect tire slippage, calculate roll angle, measure steering rate, and generate both direct balance commands and steering augmentation commands. This multi-functionality allows the system to reduce CMG energy consumption through steering augmentation without adding dedicated hardware, thereby improving energy efficiency while limiting complexity increase.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Embodiments of the invention describe methods, apparatuses, and systems for control of a two-wheeled self-balancing vehicle. Embodiments of the invention include a control system for a two-wheeled vehicle, the control system including an inertial measurement unit (IMU); one or more control moment gyroscopes (CMGs); one or more CMG controllers to control the one or more CMGs; an accelerometer to measure a y-axis acceleration for the vehicle, the y-axis being perpendicular to a direction of travel of the vehicle and parallel to a ground surface; and a processing element to calculate a roll angle for the vehicle based at least in part on the y-axis acceleration measured by the accelerometer, determine a force component based at least in part on the calculated roll angle, and generate a CMG command for a CMG gimbal rate based at least in part on the determined force component.