Player training robot "Sun Chaser" 1.0

0. Without further ado, let's get to the machine!!!
  The demonstration video has been uploaded to Bilibili, and feedback is welcome:
【Player Training Robot "Chasing the Sun" 1.0 Demonstration】
https://www.bilibili.com/video/BV1EK411U7s5/?spm_id_from=333.999.0.0&vd_source=ec87b7964c869f0403643da3947fe0c2
All project data links are below the video ┗|｀O′|┛ Aww~~
 
1. Research Background:
     Physical exercise can enhance physical fitness and provide a material basis for a healthy personality. The famous sports educator Mr. Ma John once said: "Sports is the best tool for cultivating a sound personality." Many people choose
ball sports , so reasonable training is particularly important for a beginner who is just starting out in ball sports. However, traditional manual training requires a high level of coaching skills and is generally not cheap,
which makes some ball sports enthusiasts hesitate.
    Therefore, developing a high-performance player training robot system to act as an 'assistant coach' for training players is of paramount importance! Thus, the following player training robot, "Chasing the Sun," was created.
 
 
 
2. Machine Introduction:
2.1 Gradient diagram of the 3D model and physical object of the
"Chasing the Sun" robot: 2.2 Overall design block diagram and model representation of the "Chasing the Sun" robot:
 
From the two images above, we know that the robot consists of four parts: a moving mechanism (chassis), a ball-collecting mechanism, a lower launching mechanism, and an upper launching mechanism. We will explain each part below .
 
 
 
3. Machine Structure Explanation:
 
3.1 Moving Mechanism (Chassis)
1. The chassis is a relatively simple planar mechanism built from aluminum tubes. From the exploded view, we can see that the main components consist of four sets of M3508 brushless motors, a C620 motor speed controller, an omnidirectional engine wheel, and a positioning system module.
2. The yellow connecting piece is made of epoxy board processed by a carving machine.
 
 
3.2 Lower Launching Mechanism
1. Aluminum tube frame;
2. The friction wheel drive motor is an M3508, driven by the high-speed end without deceleration;
3. The ball-pushing cylinder uses a CDJ2KB series non-spinning cylinder; one cylinder is sufficient to achieve the desired function.
 
 
3.3 Upper Launching Mechanism
1. Aluminum tube frame;
2. The friction wheel drive motor is MN5212, and the motor driver is the open-source odrive;
3. The ball-pushing cylinder is a CDJ2KB series non-spinning cylinder, one of which can achieve the desired function;
 
 
3.4 Ball-grabbing mechanism
: 1. Aluminum tube frame;
2. The actuator of the ball-grabbing mechanism is a finger cylinder;
3. The flipping drive motor is M3508;
 
 
 
4. Explanation of the main mechanism control principle of the machine:
 
4.1 Moving mechanism (chassis) ---- Omnidirectional wheel chassis ******************************************************************************************************************************************
The omnidirectional wheel chassis can achieve omnidirectional movement, as shown in the figure. Is
 
this what is meant by omnidirectional movement?
No!
 
 
Achieving the above movement is the specialty of the omnidirectional wheel. How is it achieved?
The control of the omnidirectional wheel chassis will be explained in detail below. GO!
 
 
Problems to be solved: How to solve for the speed of the four wheels -- V wheel?
 
 
 
Problem: How to solve for the speed of the chassis -- Vox, Voy, w?
 
 
So far, we have derived a chassis control algorithm for angle 'a' during the motion process. Below, we will derive all the motion processes:
 
 
1. The machine needs to reach the target state in the upper right . 2. The machine needs to reach the target state
 
 
in the upper left . 3. The machine needs to reach the target state in the lower left. 4. The machine needs to reach the target state in the lower right . At this point, we have completed the derivation of all processes. If you've persevered this far, congratulations, you're almost there! For tutorials on the CoppeliaSim simulation software, please refer to 【Vrep(CoppeliaSim)-Simulink】Making Robot Simulation Simple V-rep (Part 1)_bilibili_. The usage of Lua is similar to C/C++, and readers with C/C++ experience can quickly get started. Here's a Lua tutorial: https://www.runoob.com/lua/lua-tutorial.html OK, after verifying and perfecting the chassis control algorithm using the above simulation software, we can start debugging the actual machine. The embedded software development platform used in this machine development is Keil uVision5 and STM32CubeMX. The code is commented and corresponds to the code in the simulation software CoppeliaSim, so it should be relatively easy to understand. I won't go into too much detail, but the hardware circuit is simplified as follows: After all other preparations are completed, the chassis can be deployed and debugged! At this point, the control algorithm for the omnidirectional wheel chassis has been explained! Feel free to leave a message if you have any questions. I believe that by referring to the above tutorial, everyone will be able to have their own truly omnidirectional moving chassis. 4.2 Launching Mechanism ---- Friction Wheel Launch ****************************************************************************************************************************************** 1. Composition: The friction wheel has two parts. The outer layer contacts the projectile and is generally made of a soft material with high surface friction. The inner part is a motor acting as the power source. 2. Principle: A pair of friction wheels rotate in different directions. The projectile contacts the friction wheel from the first position, is squeezed by the friction wheel to the second position to complete acceleration, and is finally launched at high speed. The trajectory of the friction wheel is difficult to make very stable, meaning that it will deviate when aiming and launching. What factors affect the projectile launch? 3. Factors affecting stability: Friction wheel material, friction launch structure, size and spacing, friction wheel motor, and friction wheel ESC (electronic speed controller). Friction wheel materials: 1. Silicone friction wheel:    Early friction wheels were made of silicone. However, when the friction wheel rotates at high speed, the part in contact with the projectile is easily expanded due to centrifugal force and friction. If it is not reinforced circumferentially with steel wire, the silicone wheel will easily detach under tangential force after long-term friction. 2. Polyurethane friction wheel:
 
 

 
 

 
 

 

 
 

 
 

 
 

 
 


 
 

 

 
 


 
 

 

 
 

 
 

 

 




   How to solve the problem of friction wheel detachment? In the manufacturing industry, there is an important process called rubber roller technology. It uses metal and other materials as the inner core, covered with a rubber roller (a donut is a type of roller). It can effectively bond the rubber and metal together, preventing detachment.
The outer rubber material is polyurethane, which is polymerized from polyester (or polyether) and diisocyanate compounds. It has advantages such as wear resistance, tear resistance, and aging resistance, making it very suitable as a friction wheel for competitions.
 
Has the friction launch structure
changed?
Yes, in order to obtain a reliable friction acceleration effect, friction launch has evolved from the initial dual friction wheel to many new structures
 
.
Single friction wheel structure: Four friction wheel structure and three friction belt structure: This part of the friction launch structure will be explained in detail in section 4.3 Launch Mechanism 2nd Generation, and will not be repeated here
. If the friction wheels are too large and the spacing is too small, the first shot will be subjected to a large compressive force to achieve a high rate of fire. However, the reaction force on the friction wheels will also reduce their rotational speed, resulting in a significant decrease in the rate of fire for the second shot. This problem becomes very noticeable when a very high firing rate is required, and is one of the important reasons for the instability of the friction wheel trajectory. The greater the torque and moment of inertia of the motor driving the friction wheel, the smoother the rotation and the more stable the trajectory. However, a stronger motor also means a greater weight. If the firing mechanism is too heavy, it becomes difficult to control it for rapid aiming. Friction wheel electronic speed controllers (ESCs) can detect and control the friction wheel's rotational speed in real time through an encoder and provide feedback. Some ESCs have better internal algorithms and can effectively control the motor speed without feedback. The open-source odrive driver solution can be used: 4.3 Launching Mechanism 2nd Generation ****************************************************************************************************************************************************** To obtain a reliable friction acceleration effect, friction launching has evolved from the initial dual friction wheel to many new structures . Dual friction wheel structure: -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- Single friction wheel structure: Although it only has one friction wheel, it has a long friction acceleration section, ensuring the friction acceleration effect! ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- Four-Friction Wheel Structure: The left image shows a front-to-back arrangement for multi-stage acceleration; the right image shows a circular distribution for omnidirectional acceleration .--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- Three-Friction Belt Structure: The friction belt structure allows the ball sufficient acceleration time .------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- Based on the analysis of the characteristics of the above various friction launch structures, the 'Sun Chaser' Launch Mechanism 2nd Generation was born! It consists of two parts: launch and elevation. ********** ...

 

 
 



 


 




 
 
 

 


 










 

 


 
**************************************************************************************************************************************************************************************************************************
The friction belt structure component is as follows:
**************************************************************************************************************************************************************************************************************
Dual friction belt launching mechanism:
**************************************************************************************************************************************************************************************
Pitch adjustment mechanism:
******************************************************************************************************************************************************************************************
Hardware circuit:
 
 
 
【Player training robot "Chasing the Sun" 1.0 demonstration】
https://www.bilibili.com/video/BV1EK411U7s5/?spm_id_from=333.999.0.0&vd_source=ec87b7964c869f0403643da3947fe0c2
All project data links are below the video ┗|｀O′|┛ Aww~~