Hand Tracking in Augmented Reality (AR)

Hand Tracking in Augmented Reality (AR)

In the previous lesson, we learned a new way to implement location-based augmented reality without using GPS. We learned how to position objects in augmented reality accurately and offline. In this video, we want to use a new and handy feature for augmented reality to increase the productivity of AR applications and provide practical freedom for the user. If you want to know how you can implement this, continue this lesson by watching the video version of the lesson at the link below: https://www.youtube.com/watch?v=zJq1gp0t_SU You can also watch more lessons about Virtual Reality (VR) and Augmented Reality (AR) in the…
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Location-based Augmented Reality (AR) without GPS

Location-based Augmented Reality (AR) without GPS

In the previous lesson, we learned about location-based augmented reality with GPS and how one or more geographic coordinates can be used as operators in the content displayed by augmented reality. We also talked about the challenges in this area and learned how to overcome them. In this lesson, we will learn about a new approach to implement location-based augmented reality. In this new method, the device does not need to be connected to any GPS satellites or even the Internet, and all calculations will be done offline. If you want to know how you can implement this, continue this…
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Training Modalities in Rehabilitation Robotics

Training Modalities in Rehabilitation Robotics

As we saw in the previous two lessons, rehabilitation robots can generally be categorized as upper-limb rehabilitation robots and lower-limb rehabilitation robots. No matter which part of the body they are targeting to rehabilitate, they can provide four different types of physical therapy that should be chosen based on the patient's needs. They are passive rehabilitation, active-assisted rehabilitation, active-resisted rehabilitation, and bilateral manipulation. Passive Rehabilitation Passive Rehabilitation can be used at the early stages of the impairment where the affected limb has no movement. In this type of therapy, the robot moves the affected limb of the patient through a…
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Lower-Extremity Rehabilitation Robots

Lower-Extremity Rehabilitation Robots

Previously, we learned about rehabilitation and the importance of robot-aided rehabilitation. We have also seen some of the upper-limb rehabilitation robots and how they operate. In this lesson, we will become familiarized with lower-limb rehabilitation robots that are helpful for patients with lower-extremity disorders. Lower-extremity exoskeleton robots can be designed to help the movement of a specific joint, or they are designed for gait rehabilitation. They can also serve as assistive devices to perform activities of daily living (ADL). Joint-specific Rehabilitation/Assistive Exoskeleton Robots Joint-specific rehabilitation/assistive exoskeleton robots are used for body joints rehabilitation and can be made to rehabilitate or…
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Upper-limb Rehabilitation Robotics

Upper-limb Rehabilitation Robotics

You may have already heard about rehabilitation, or you may have used some of the services in the past, or the first thing that comes to your mind is Britney Spears. But whatever you've already had in your mind, rehabilitation refers to enhancing or restoring the movement and quality of life for people with disabilities or other impairments due to diseases or injury. By definition, rehabilitation refers to help restore movement and function to people with disabilities caused by diseases or injury. However, doing repetitive tasks for long periods of time is daunting and less intensive than needed for proper…
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Homogeneous Transformation Matrices to Express Configurations in Robotics

Homogeneous Transformation Matrices to Express Configurations in Robotics

Up to this point, we have discussed orientations in robotics, and we have become familiarized with different representations to express orientations in robotics. In this lesson, we will start with configurations, and we will learn about homogeneous transformation matrices that are great tools to express configurations (both positions and orientations) in a compact matrix form. This lesson is part of the series of lessons on foundations necessary to express robot motions. For the full comprehension of the Fundamentals of Robot Motions and the necessary tools to represent the configurations, velocities, and forces causing the motion, please read the following lessons…
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Cayley-Rodrigues Parameters to Express Orientations in Robotics

Cayley-Rodrigues Parameters to Express Orientations in Robotics

In this lesson, we will become familiarized with another representation for orientations in robotics that is called Cayley-Rodrigues Parameters. Cayley-Rodrigues parameters provide local coordinates for SO(3). They are local coordinates because the representation is not singularity-free, and not all orientations can be expressed by them. However, they have properties that make them intriguing. This lesson is part of the series of lessons on foundations necessary to express robot motions. For the full comprehension of the Fundamentals of Robot Motions and the necessary tools to represent the configurations, velocities, and forces causing the motion, please read the following lessons (note that…
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Explicit Representation of the Orientation: Exponential Coordinates

Explicit Representation of the Orientation: Exponential Coordinates

In the previous lesson, we became familiar with rotation matrices, and we saw that the nine-dimensional space of rotation matrices subject to six constraints (three unit norm constraints and three orthogonality constraints) could be used to implicitly represent the three-dimensional space of orientations. There are also methods to express the orientation with a minimum number of parameters (three in three-dimensional space). Exponential coordinates that define an axis of rotation and the angle rotated about that axis, the three-parameter Euler angles, the three-parameter roll-pitch-yaw angles, the Cayley-Rodrigues parameters, and the unit quaternions (use four variables subject to one constraint) are some of…
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Implicit Representation of the Orientation: a Rotation Matrix

Implicit Representation of the Orientation: a Rotation Matrix

In the previous lesson, we became familiar with the concept of the configuration for the robots, and we saw that the configuration of a robot could be expressed by the pair (R,p) in which R is the rotation matrix that implicitly represents the orientation of the body frame with respect to the reference frame and p is the position of the origin of the body frame relative to the space frame. In this lesson, we will focus on the orientation, and we will see that we can implicitly represent the orientation using powerful tools named rotation matrices, and we will…
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Fundamentals of Robot Motions: Configurations (Introduction)

Fundamentals of Robot Motions: Configurations (Introduction)

This post is part one of the series of lessons on the fundamentals necessary to represent the robot's configuration, and it gives an introduction to what we mean when we are talking about representing a robot's configuration. In previous lessons, we learned that the robot's configuration answers the question of where the robot is, and we saw that there are two ways to represent the robot's configuration: Implicit representation, where the configuration is represented by embedding the curved space in higher-dimensional Euclidean space subject to constraints and explicit representation where configuration is represented with a minimum number of coordinates. You…
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