1. TIGERBOT 2 REJUVENATION

2. PREVIOUS STATE OF PROJECT
Tigerbot 2 Previously used Custom Computing solutions
Implicit to these solutions were
Custom Proprietary hardware (RowBoard)
Custom Libraries
Deprecated version of ROS
No Visualizations
No Path or Trajectory planning

3. Goals Of Project Convert Tigerbot To Current Ros Version
Provide a ROS package that Can be Used Multiple Linux Platforms
Single Board Computer Running Linux
Laptop or CPU Running Linux
Adding Trajectory And Path Planning through the use of Moveit! and the use of OMPL (Open Motion Planning Library)
Implement Balancing And WAlking Algorithm

4. Embedded Controller Changed / Added
Servo Control Migrated From SSC32 Servo Controller To the Teensy 3.1 Arm Cortex M4
Provided the Ability to Publish directly to ROS topics
More control and options for controller configuration and implementation.

5. Primary Communication
Communication Over USB for High Bandwidth Trajectory position Commands
Commands can originate from any linux machine running ROS
Any Single Board Computer
Laptop / CPU

6. Xtion IMU IMU Laptop Or Odroid USB BUS Tigerbot Teensy Left Side
Point Cloud
Depth Spectrum
(USB)
IMU
IMU
I2C
Direct connect to Main CPU
I2C
Direct connect to Main CPU
Laptop Or
Odroid
USB BUS
Tigerbot
Teensy
Left Side
Tigerbot Teensy
Right Side
Sensors
Sensors
Servos
Servos

7. Leg Joint Group Sensor Modules Joint Vals Pose Twist
*TF is a Transformation Message that updates the Robot Pose for Motion Planning Plugins
Joint Vals
Pose
Twist
Linear and Angular
Effort
Torque
Motion/Trajectory Planner
TF*
Robot State
CPU
RosSerial (USB) Joint Group message (6 Values)
Leg Joint Group
Teensy
Position
Hip Rotation Servo
Leg
Servo Feedback
Position
Hip lift Servo
6 PWM Control
Servo Feedback
Position
Hip Side Lift Servo
Servo Feedback
Servo FeedBack
Callback
Position
Knee Servo
Servo Feedback
Position
Ankle Lift Servo
Sensors Interface
Servo Feedback
Position
Ankle Side Lift Servo
Servo Feedback
Sensor Data from Interfaces
Sensor Modules

8. User Interface (RViz, MoveIt, etc.)
Scene Information, Robot State, Motion Request
Motion Response, Collision Avoidance
URDF, Config
Joint States, Transformation Matrix
Robot Model
ROS Interface
Load/Unload Controllers
Controller Manager
Controller
Feed commands to hardware interface from ROS interface
Hardware Resource Interface
Communicate with the hardware
Hardware Interface
readHW()
writeHW()
readSim()
writeSim()
Hardware
Gazebo

9. Hardware Abstraction Layer Isolates Embedded System
Software - ROS
Hardware Resource
Interface Layer
Hardware Abstraction Layer
Isolates Embedded System
Embedded side can be changed without affecting high level stack
Hardware Interface can be be emulated by Gazebo Simulator
Real Robot
RobotHW
Teensy
Hardware Interface
L_Arm_Command
L_Arm
R_Arm
L_Leg
R_Leg
L_Arm
R_Arm
L_Leg
R_Leg
L_Arm_State
l_arm (URDF)
left_shoulder_lift_joint
left_shoulder_side_joint
left_shoulder_rot_joint
left_elbow_joint

10. Description Of Tigerbot describes joint relations
XML snips from URDF
Torso
(Base Link)
Parent Child Relationships
<joint
name="right_shoulder_side_joint"
type="revolute">
<parent
link="torso" />
<child
link="right_shoulder_side_link" />
</joint>
Description Of Tigerbot describes joint relations
creates a joint link chain for Inverse kinematic solvers.
Allows For accurate representation of Robot in Software
Joint Names used to register joints with ros controllers
Right Shoulder Joint
Right Shoulder side Link
<joint
name="right_shoulder_rot_joint"
type="revolute">
<parent
link="right_shoulder_side_link" />
<child
link="right_shoulder_rot_link" />
</joint>
Right Shoulder rot Joint
Right Shoulder rot Link
<joint
name="right_elbow_joint"
type="revolute">
<parent
link="right_shoulder_rot_link" />
<child
link="right_elbow_link" />
</joint>
Right Elbow Joint
Right Elbow link

11. Frame Transformations
Teknic HLS
(High level Status bit)
Gazebo Simulation
URDF
(Unified Robot
Description File)
Parameter Server
(contains robot description)
Joint_states
(feedback)
Robot State Publisher TF
(Transformation Frame package)
Visualization
(Rviz)

12. CPU IMU Teensy Publish Subscribe Imu Topic <sensor_msgs/Imu>
Header
Sequence ID
Timestamp
Frame ID
Accel / Gyro Info
Orientation(X Y Z W)
Angular Velocity(X Y Z)
Linear Accelerations
Joint[n]_command
<trajectory_msgs/JointTrajectory>
Header
Sequence ID
Timestamp
Frame ID
Joint names
Joint Trajectory Points
Positions
Velocities
Accelerations
Effort
Duration
CPU
IMU
Teensy
Joint[n]_state
<sensor_msgs/JointState>
Header
Sequence ID
Timestamp
Frame ID
Name
Position
Velocity
Effort
Publish
Subscribe

13. Using joint trajectory controllers for motion
Problems Encountered
Joint Limits Not Responding Correctly
Coordinate Frames Were Not placed with Care Initially.
Attempts to re-export model did not go as planned
Moving Forward
Using joint trajectory controllers for motion
Moveit seems to cause more Problems than it solves as of this point (for motion planning)