q1anwan/bananabot

Graduate design.

BananaBot - Balancing Robot Type B

BananaBot is a kind of five-link dual-wheel balancing robot. It's based on balancing infantry robot in the RoboMaster competition.
BananaBot is a graduate design of Dalian University of Technology.

Overall of robot

BananaBot has three main components: the body-box, the legs, and the wheels. The structural design and kinematic model derivation are both based on this.

Here lists more paramaters about robot:

Parameter Name	Value	Unit
Mass	3.9	kg
Maximum Load	2.5	kg
Maximum Acceleration	1.0	m/s²
Maximum Linear Velocity	1.2	m/s
Maximum Jump Height	0.2	m
Shortest Effective Pendulum Length	0.12	m
Longest Effective Pendulum Length	0.32	m
Maximum Left-Right Pendulum Height Difference	0.15	m
Endurance Time	1.0	h

Here is the hardware connection of BananaBot:

Kinematic of robot

The build of the kinematic model is based on this paper¹. The robot is approximated as an inverted pendulum model composed of a body-box, a rigid pendulum rod, and wheels. And we construct the rotational and translational kinematic equations for this system.

The system state variables are defined as: [ \mathbf{x} = [\theta, \dot{\theta}, x, \dot{x}, \phi, \dot{\phi}] \quad (3.10) ]

The system output variables are defined as: [ \mathbf{u} = [T, T_p] \quad (3.11) ]

Simplify using MATLAB symbolic computation and linearize around the equilibrium point. This content can be found in the MATLAB folder, as LQRModule.m.

Controller of Robot

We have the following main controllers:

• LQR Controller
• Equivalent Pendulum Length Controller
• Fork Controller
• Heading Angle Controller
• Roll Angle Controller

As well as the following observers:

• Body Attitude EKF (Extended Kalman Filter)
• Anti-skid KF (Kalman Filter)

And the transformation:

• VMC Transformation

Among them, the VMC (Virtual Model Control) controller utilizes the statics of a five-bar linkage to achieve bidirectional force mapping between the pendulum and the motors.

Software

• Code generator: STM32CubeMX-6.11.1
• Tools chains: arm-none-eabi-gcc
• Debugger: OpenOCD + GDB(Windows need mingw64)
• STM32CubeH7 Firmware Package V1.11.0 / 04-Nov-2022
• STM32CubeExpansion_AZRTOS-H7 V3.2.0
• OneMessage - Message System
• WHX EKF - AHRS

Software construction list here:

USB and Mavlink haven't been fitted in this version of codes.
Real codes may not 100% fit this picture.

BTW, LVGL files in this project are useless.

Footnotes

1. 陈阳, 王洪玺, 张兰勇. 轮腿式平衡机器人控制[J]. 信息与控制, 2023, 52(05): 648-659. https://doi.org/10.13976/j.cnki.xk.2023.2533. ↩