SENDAI, Japan — A car parked illegally on a city street comes under suspicion by law enforcement agents who believe it may be packed with explosives. They send in two robots to lift the vehicle and move it to a designated safe location where bomb disposal units can take over.
While the above scenario is fictional, it is one of the visions that Kazuhiro Kosuge of Tohoku University’s bioengineering and robotics department has for his invention, the iCART — Intelligent Cooperative Autonomous Robot Transportation.
The iCART consists of two mobile robots that collaborate to carry four-wheeled vehicles to and from confined spaces. Each rectangular robot spans about the length of a small automobile and reaches a height of an average person’s shins. The robots are composed of three modules: mobile base, lifter and connecting.
The mobile base module sits on casters that can coast along the floor in all directions. It contains the lifter module that detects the center of a vehicle’s wheels, positions the four lift-bars around the tires and raises and supports the weight of the car. The connecting module serves as the link between the mobile base and lifter modules and measures the pushing and pulling forces to allow for movement.
One robot grasps two wheels on one side of the vehicle, and its counterpart does the same on the other side. A motion control algorithm based on a leader-follower concept coordinates the transport of the car. The motion command is given to the first robot, and the follower robot estimates the motion given to the leader. They move in tandem, even if the casters experience slippage along the floor.
The most difficult part in designing the system was figuring out how to grasp and secure the automobile without doing damage, says Kosuge. Because there are more than 1,000 types of passenger vehicles, each with unique jack-up points on the chassis, the team determined that the simplest way to lift vehicles was to pick them up by their tires. Though wheels come in various sizes, the robots are able to detect the center points of any tires and adjust the lifting bars accordingly.
During a demonstration of the test model in the lab, one of Kosuge’s graduate students controls the system with a laptop computer that is connected via a cable to the leading robot. The robots maneuver into position on either side of a four-wheeled scooter. Their lifters slide under the scooter’s tires and buoy the vehicle. The iCART glides from one side of the room to the other and places the vehicle safely back on the floor.
Kosuge says the system will be able to handle two-axle vehicles of all dimensions, from small cars to vans.
The robots can be configured for wireless tele-operation using a joystick, but the ultimate goal, he says, is to take the human controller out of the equation completely and have the systems operate autonomously. That type of operation will require more research, he acknowledges.
The team has been working with a Japanese company, Ishikawajima Transport Machinery Co., which is developing a prototype based on the iCART test model. If all goes well, says Kosuge, the company plans to commercialize the technology in the near future for application to Japan’s parking garages, many of which are narrow, multi-story complexes that feature vehicle elevators and turntables. Drivers typically pull the car onto the elevator with guidance from attendants who then take the car up to an appropriate level and park it in a vacant spot. The process is tedious and time-consuming and requires parking attendants to be highly proficient at navigating vehicles in tight places.
“With the introduction of the system, we eventually could automate the whole process,” says Kosuge. “The system could be operated without any operator. This is our goal.”
The iCART not only could be applied to Japan’s parking system, but also to other industries, such as ferries and towing services, where the transportation of automobiles are required without having a driver inside of the car, he adds.
For the earlier law enforcement scenario, Kosuge says his team would need to modify the iCART to handle such cases on urban streets. But without any changes, the system could be applied to a parked vehicle in a lot with space for the robots to maneuver.
Kosuge envisions a day when people will drive to a restaurant or hotel and do not have to hand over their keys to a parking valet. They would simply get out of the car and a pair of robots would come to park it.