An Overview of the Pivotal Robot Locomotion Principles

What is Robot Locomotion?

According to Java T Point, “Locomotion is the method of moving from one place to another. The mechanism that makes a robot capable of moving in its environment is called as robot locomotion.”

That is to say, robot locomotion is the technique of aligning multiple tools and solutions for the movement of robots. It also is the mobilization of robots within a specific environment. As a result, the concept of robot locomotion enables robots to walk, run, jump, fly, roll, crawl, swim, and glide. Moreover, it uses concepts of geometry to engage and interact with various contact points. Therefore, robot locomotion develops the ability of a static robot to dynamically reflect on its environment or terrain.

Wikipedia states, “Robot locomotion is the collective name for the various methods that robots use to transport themselves from place to place.” It also implies, “A major goal in this field is in developing capabilities for robots to autonomously decide how, when, and where to move. However, coordinating numerous robot joints for even simple matters, like negotiating stairs, is difficult. Autonomous robot locomotion is a major technological obstacle for many areas of robotics, such as humanoids (like Honda’s Asimo).”

Further, it enables robots to achieve higher efficiency, great speed, and agility to overcome impediments. Locomotion systems for robots also enable strategies to streamline functions that integrate various activities. It also helps develop designs that diversify the horizons and create patterns that enable a variety of actions. 

Key Issues for Locomotion:

Conventional locomotion systems are often unstable within complex and diverse environments. Moreover, their motions are scanty and insufficient which may lead to rigidity during various activities. Further, in the case of kinematics and dynamics, robot locomotion needs to overcome the following issues:

• • Stability:

• • • Quantity, Position, and Geometry of contact points.
    • Gravitational Centre Point.
    • Stability during static and dynamic status.
    • The propensity of the surface, environment, and terrain.
      

• • Characteristics of Contact:
    • The point of contact is the path’s size and shape to reach it.
    • The angular position of the Contact.
    • The amount of friction, abrasions, and obstacles to reach the point of contact.

• • Type of Environment:

• • • The structure, formation, and composition of the environment.
    • The medium and surface tension of the environment.

Types of Robot Locomotion

There are many types of robot locomotion and they are as follows:

• Wheeled Locomotion:

Wheeled locomotion is a seamless and popular mechanism for robot locomotion. It plays a pivotal part in the design and innovation of mobile robots. It also helps enhance the capability of locomotive efficiency and is easy to monitor. Further, balance is a simple feature for wheeled locomotion as it maintains interminable contact with the surface. 

For example, R2D2 from Star Wars is a great example of wheeled locomotive robots. Moreover, it applies various techniques to maintain balance and stability depending on the number of wheels. 

Types of Wheeled Robot Locomotion:

• • Castor Wheel
  • Standard Wheel
  • Ball or Spherical Wheel
  • Swedish 45 and Swedish 90 Wheels

• Legged Locomotion:

Legged Robot locomotion is a design for rough and turbulent surfaces. Moreover, it enables the capability of robots to climb, cross, hold, walk, etc. Further, it uses limb-like components to make primitive decisions and navigate irregular terrains. It also offers a variety in the number of limbs according to the requirements. Further, the more limbs the robot acquires, the more coordination and degree of freedom (DOF) it requires. As a result, for every DOF there is a requirement for one joint. Therefore, each joint is mechanized by a servo. Hence, a robot with 4 limbs would require a minimum of eight servos to cross terrains. It may also lead to difficulties while implementation due to various other stability and balance issues.

Further, C3PO another popular example from Star Wars is another great example of a legged locomotive robot. Moreover, legged locomotion requires more power and agility to demonstrate various activities. 

For instance, let us consider a formula for the various possible events, depending on the number of limbs which is N=(2X-1)!. Here X is the number of limbs or legs and N is the number of possible events.

Therefore, let us consider the X=2. Hence while applying the formula, here is the possibility of events,

N=(2X-1)!

N=(2*2-1)!

N=3!

N=3*2*1

N=6

As a result, there are six possible events that occur when a robot has two limbs. Hence, here are the logical events:

• • • • • Raising the right leg.
        • Raising the left leg.
        • Lowering the right leg.
        • Lowering the left leg.
        • Raising both the legs together.
        • Lowering both the legs together.

• Slip/Skid Locomotion:

Slip/Skid Locomotion refers to the use of tank sprocket technology to traverse through various terrains. Moreover, the robot requires steering while making movements to drive at various speeds, directions, and surfaces. It also provides higher stability as it extensively keeps contact with the surface. For example, the snail droid or NR-N99 Persuader-class droid enforcer from Star Wars stands as a great example. Moreover, while wheeled robots are great on flat surfaces, they may face resistance on a frictional surface. Hence, slip/skip locomotion helps keep traction on various surfaces and rough terrains. 

• Walking Wheels:

Walking wheels refer to the concept of combining legs and wheels in locomotion. That is to say, it uses limbs to help walk, jump, climb, etc. while the wheels provide efficiency on flat surfaces. Further, the idea is to integrate the solutions and the best quality of the locomotive types. Moreover, it provides the robot with maximum mobility and control. It also mitigates the issue of stability while using wheels on flat surfaces. It also increases the possibility of covering various environments and terrains using multiple limbs.

Here are the Pivotal Robot Locomotion Principles

Robot locomotion takes its inspiration from the various beings and animals in its environment. Moreover, robot locomotion principles are the keys to optimizing the capabilities of a robot in various environments. Hence, here are the Robot Locomotion Principles to reach maximum potential:

• Metabolic Cost Model:

Faraji S., Wu A.R., and Ijspreet A.J. put forth a fundamental cost model to forecast trends in general conditions of walking. Moreover, in 2017 Faraji and Ijspreet develop a 3D linear moving model known as 3LP. Further, the model simulates the stability and movement in standard surfaces. It is also a vertical simulation of movements that incorporates the Centre of Mass, which provides it with a velocity redirection cost. Moreover, it includes a ground clearance cost for walking using a non-zero ability of leg lift. Further, the cost model includes various charges that support the extensive limbs and muscles while moving. That is to say, it continuously calculates the cost of muscle efficiency to simulate the frequency, width, mass, surface tension, and gravity force.

• Bio-influencing Insights:

A lot of robotic movements and locomotion take inspiration from their environment. Moreover, depending on an environment’s type, condition, and surface, it utilizes insights from the ecological components. Therefore, it can easily maintain agility, stability, and instinct while enduring environmental challenges. Further, it amalgamates insights from biomechanics, sensory-motor control, and engineering. It also paves the way for robotic locomotive abilities to develop and transform as per requirements.

• Primitive Concept:

Robotic applications have a dynamic influence in the real world. Moreover, it uses logical reasoning, decision-making, and high-level control according to data. As a result, it takes into consideration characteristics and movements to plan gesticulations. Therefore, regardless of its environment and ecology, it can develop its movements and trajectories. Hence, by using motion planners, indicators, sensory information, and environmental dynamics robots can become more efficient and make transient movements.