Module 2 - Locomotion and Wearable Motion Tracking Flashcards
What is the Definition of Energy?
- Capacity for doing work
What does energy exist in?
- Potential Energy
- Kinetic Energy
- Thermal Energy
- Electrical Energy
- Chemical Energy
- Nuclear Energy
- Other Forms
What is the Definition for Work?
- The energy in the process of transfer from one physical system to another
What is Potential Energy?
- The energy that a physical system stores because of its position
ex. springs
What is Gravitational Potential Energy?
- Energy stored in a physical system because of its vertical position or height
What is Kinetic Energy?
- The energy that a physical system possesses due to its motion
What is total energy?
- The summation of all types of energy stored in a system
What is energy consumption or dissipation?
- The energy which is utilized to produce work and as a result dissipated
What is the exchange of energy?
- Example of slider with no friction: The Roller Coaster
What is the Energy cost of transport?
- Due to friction in joints and the environment, we spend energy to keep up the locomotion velocity
How is Expenditure Energy Measured?
- Oxygen consumption
- Production of Carbon Dioxide
What are the 2 mechanisms for minimizing energy expenditure??
- Fall forward and step to catch ourselves: exchange between kinetic and gravitational potential energy
- Shut down most muscles during the swing phase: Negative work to prevent the leg from going forward
How does friction help with acceleration and breaking when driving?
Acceleration
- Wheel pushes back, friction pushes forward
Breaking
- Wheel attempts to stop pushing back, friction pushes car back
What is the definition of Ground Reaction Force?
- Newtons Third Law: use coordinate system to help
What is an EMG?
Electromyography
- Technique for evaluating and recording electrical activity produced by skeletal muscles
- Voltages, not forces
- Need to modify the voltages to estimate forces
How do we measure external forces during walking?
- Force Plates
What are the events of the Gait Cycle?
- Right Heel-Strike (0%)
- Left toe-off
- Right mid-stance
- Left heel-strike (50%)
- Right toe-off
- Left mid-stance
- Right heel-strike (100%)
What is Joint Angle?
- A biomechanical measure that has been used in numerous studies
Is there an Ideal Gait Cycle?
- Mathematically, Yes
- Realistically, No
How do you compare gait cycles?
- Observation of joint angle
- other gait parameters
In what ways can you measure a gait cycle?
- Conventional Method: Goniometer
- Video-based motion capture systems
- Kinect
- IMUs (like in the matlab phone app)
For the Motion Capture device, what are the reference points and origins?
- Origin is point where the axes systems intersect
- Origin divides each axes into two halves
- Coordinates of the origin are always zero
What is a coordinate system?
- Uses one or more numbers, or coordinates, to uniquely determine the position of the points
What is a rigid body?
- Solid-body in which deformation is zero or so small it can be neglected
What do we assume when using the motion capture system?
- Bones are rigid bodies in humans
Where should you put the 3 markers for a motion capture system?
- on the bony landmarks
How are coordinates defined on the human body?
- Using anatomical coordinate system
What are some limitations of the Motion Capture System?
- Limited Space
- Typically Indoor
- Not Portable
- Expensive
- Needs staff
- Time-consuming Use
- Not easy to use
What are the advantages of using the motion capture system?
- accurate movement in space
- accuracy of angles of measurement
- Rigid on the body
What are the advantages of using IMUs?
- Not limited by space
- Portable
- Reasonable Cost
- Can be run by ourselves
- Fast and Easy to Use
What are the limitations of using IMUs?
- Slips on the Body
- Accuracy
- Angles Measurement
- Does not give position data (only rotational, velocity, and acceleration)
