ESC Open-Loop Control After Flight Controller Signal Loss
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Solution Overview
Problem
Multi-rotor aerial robotic vehicles are dynamically unstable and can become rapidly unstable upon loss of control signals from the main flight controller, leading to potential collisions and damage due to the reliance on active control for attitude, position, and velocity stabilization.
Innovation Solution
Implementing open loop flight control methods within electronic speed controllers (ESCs) that allow independent motor control based on pre-stored or determined sequences of motor control instructions, enabling the robotic vehicle to perform emergency maneuvers such as controlled landings or minimize damage in the event of flight controller failure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the robotic vehicle relies on active control by the main flight controller for stabilization, then flight control precision is improved, but system reliability deteriorates when the flight controller fails
Solution Approach 1:
The control system is segmented into two independent parts: the main flight controller for normal operation and the ESCs with independent open-loop control capability for fail-safe operation. Each ESC can independently execute pre-stored motor control instructions when the flight controller fails, ensuring system reliability without compromising flight control precision during normal operation.
Solution Approach 2:
The ESCs are pre-programmed with open-loop motor control instructions and fail-safe sequences before flight operations begin. This preliminary action ensures that when the flight controller fails, the ESCs can immediately execute pre-prepared control sequences to stabilize the vehicle and perform safe landing, thereby improving system reliability without affecting normal flight control precision.
2Reliability
If the ESCs execute pre-stored motor control sequences without sensor feedback, then system reliability is improved during flight controller failure, but control precision deteriorates
Solution Approach 1:
The open-loop control sequences are designed to perform essential fail-safe functions (stabilization and safe landing) rather than full flight control. This partial action approach ensures sufficient control precision for emergency situations while maintaining system reliability, without requiring the precision of full closed-loop control during fail-safe operation.
Solution Approach 2:
The pre-stored motor control sequences include cushioning maneuvers designed to minimize impact during emergency landing. These sequences anticipate the loss of precision control and incorporate deceleration and stabilization phases that cushion the transition from flight to landing, maintaining adequate control precision for safety-critical functions during open-loop operation.
Data Source
AI summary
Various embodiments include devices and methods for controlling a robotic vehicle. Each electronic speed controller (ESC) of the robotic vehicle may receive open loop flight control information from a flight controller or another processing device of the robotic vehicle. In some embodiments, each ESC may store the provided open loop flight control information in a memory. In response to detecting a loss of control signals from the flight controller, each ESC may access the stored open loop flight control information and perform control of a motor associated with each ESC based on the open loop flight control information. The open loop flight control information may be a sequence of motor control instructions to be performed over a period of time, or parameterized information or vehicle state information that enables each ESC to generate a sequence of motor control instructions.