Simulating Riding Dynamics toward Developing a KinematicallyRealistic Mechanical Horse for Hippother

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Simulating Riding Dynamics toward Developing a
Kinematically-Realistic Mechanical Horse for
Hippotherapy Research

• Rhett Rigby

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What is Hippotherapy?

• The use of a horse as a therapy instrument to
  treat patients with many different forms of
  neuromusculoskeletal disability
• Main objective to improve neurological function
  and sensory processing
• Used to treat
• Cerebral Palsy (CP)
• Multiple Sclerosis (MS)
• Down Syndrome
• Developmental delays
• Traumatic brain injuries
• Spinal cord injuries

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How Does Hippotherapy Work?

• Mechanics
• Horse motion drives body through patterns it
  cannot perform itself
• Motions mimic those of healthy human gait
• Tunes joints, muscles, and neural pathways for
  these natural movement patterns
• Psychosocial influences
• Emotional interaction with horse encourages
  patient and stimulates good mood

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Purpose

• Until very recently, little research done to
  investigate the efficacy of hippotherapy
• To facilitate research and increase access to
  hippotherapy, Dr. Garner and I are planning the
  construction of a mechanical horse
• Purpose of this study was to compute the types of
  loads a mechanical horse needs to generate in
  order to simulate the realistic motion of a horse
  with a child rider

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Methods

• Three-dimensional computer simulations were
  performed to model the dynamic interactions
  between a saddle and a rider
• A dynamic model that consisted of four rigid
  bodies was created
• The saddle and lower torso of the rider
• The riders abdomen
• The riders upper torso, including the chest and
  arms
• The riders head, including the neck, cranium,
  and helmet

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Methods

• An inverse dynamics approach was used
• Inputs
• Three translations and three rotations
• Velocities and accelerations
• Gravity
• The mass and moments of inertia of each body
• Outputs
• The active forces of the horse
• The passive internal forces and moments
  experienced by the rider

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Animation
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Results
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Discussion

• Model Significance
• Fairly realistic model of a horse and rider
  dynamics
• Results will guide construction of a mechanical
  horse
• A mechanical horse will facilitate research and
  assist physical therapy
• Model limitations
• Model only analyzes one period of a horses gait
• Horse walks at different speeds
• Horse may correct itself to prevent the rider
  from falling off

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Future Studies

• Longer trial-run area
• More cameras need to be used to capture longer
  trial runs, both in time and distance
• More realistic inertial inputs to the model