Maple contributes to revolutionary advancements in medical robotic technology - User Case Studies - Maplesoft

User Case Study: Maple contributes to revolutionary advancements in medical robotic technology

Imagine a time in which doctors can perform surgery on a patient without having to be in the same room, or even in the same city. Modern technology, aided by tools like Maple™, is making such possibilities very real.

Maplesoft™, the leading provider of high-performance software tools for engineering, science, and mathematics, is assisting Quanser Consulting to develop revolutionary haptic (feedback) technology, taking robotically assisted surgery to the next level. Quanser is a world leader in the innovation and development of advanced control systems for industry, education, and research. 

Experimenting with haptic technology

What is Haptic Technology?

Haptics is a technology that allows human interfaces, such as joysticks, to provide force feedback cues to someone performing the procedure from a distance, making him or her feel physically connected to the remote system. Haptic technology is the key to adding sensory feedback to robots. By allowing surgeons to touch, feel, and respond to realistic sensations, haptic technology will change the face of modern-day surgery. Robotically assisted surgery allows precision robotic tools to act like a surgeon’s arms, hands, and fingers, allowing surgeons to reach areas the human hand cannot reach without making large incisions. If a surgeon using haptic technology controls the movement of a robotic arm and strikes an obstacle during a surgical procedure, he or she feels the force of the obstacle against his or her hand and can take steps to avoid it. This means that, when surgeons use haptic technology, they have a more acute awareness of what the remote system is doing. Also, they do not need to rely purely on visual feedback as they would when using traditional systems.

The resulting benefits include less patient trauma; reduced pain and blood loss; fewer complications; faster recovery times; and shorter hospital stays.

The medical robotic market has shown steady growth over the past seven years and the demand for these technologies is predicted to exceed $1 billion a year globally.

How was Maple used?

Previous haptic interfaces, developed over the years, have limited or non-driven degrees of freedom (DOF). Quanser’s 5- and 6-DOF haptic interfaces (x, y, z, pitch, roll, yaw) featuring high stiffness, high response, and minimal nonlinearities meet the requirements for successfully integrating Human-Machine interfaces into real-life biomedical engineering systems (such as medical robotics). Each degree of freedom in every high-fidelity Quanser haptic device needs at least one servomotor set consisting of a precision motor and a position sensor (encoder), which are all connected with an increasingly complex frame of linkages known as a pantograph. As the number of degrees of freedom increases, the complexity of the mechanisms providing the system inputs becomes so extreme that these mechanisms are virtually impossible to mathematically model by hand. Quanser creates complex mathematical computer models to represent a robot’s motion, and uses the predicted behavior to develop the controllers both for the robot motion and for the haptic feedback to a surgeon’s hands.

Systems of differential equations were generated
almost instantly using Maple

In order to develop the controllers, engineers at Quanser first modeled the behavior of the mechanism: a task that would have taken so long, it would not have been economically viable to do by hand. Using Maple, they could enter the basic geometric relationships that describe the pantograph, and then develop the systems of differential equations – many of which were several pages long – that modeled the kinematics and dynamics of the system. This was done almost instantly and was completely free of the typical errors inherent in manual mathematical manipulations.

Once this was done, the team could very quickly test their model by solving the equations of motion and then developing the control strategies within the Maple environment. They also used Maple’s optimized C code generation feature to export the model to Simulink® as S-function blocks for final simulation and testing before building the controllers.

“Maple is a critical part of our development process,” said Paul Gilbert, President of Quanser. “Without it, we could not have developed the mechanism models at all. Without the models, we would not be able to produce the controllers and this project would not have survived. That’s how significant Maple is to us.”

But Maple’s benefits in this area didn’t stop there. The team’s work is captured and documented within Maple technical documents. “This saves a huge amount of time if we ever need to make a design change, or use the design as a basis for a new one,” said Ryan Leslie, Design Engineer at Quanser. “We can simply open the appropriate Maple document, make the changes, and regenerate the code. We should not underestimate how valuable this capability is to an engineering project like this.”

Finally, Maple also plays a very important educational role in Quanser’s product offerings. Because all of the underlying mathematics can be fully disclosed, Quanser provides curricular material along with a range of Maple documents to enhance the teaching and understanding of control development for all their mechatronic experiments, including the haptic devices.

Other applications

Quanser’s work in haptics has far-reaching implications for the future of robotically assisted surgery such as brain microsurgery, nanosurgery, and telesurgery (long distance surgery). Its control technology is employed in fields such as aerospace, military, robotics, and other medical assistive devices. Maple was also used in the design of the Freehand Script Reproduction Robot, which is at the heart of the LongPen™, the world’s first long distance handwriting device by Unotchit (www.longpen.com). The world-famous writer Margaret Atwood and forty other high-profile writers have used the LongPen to autograph copies of their books in stores thousands of miles away.

The time for remote surgery with a sensory element in surgical robots is here. In the coming years, watch for more radical and revolutionary control devices assisted by the computational power of tools like Maple.

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