Lexus RX Comes with 'Remote Touch' Haptic Interface

Feb 3, 2009
Tatsuhiko Hayashi, Nikkei Automotive Technology
Fig 1: The "Remote Touch" incorporated in the "Lexus RX"
Fig 1: The "Remote Touch" incorporated in the "Lexus RX"
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Fig 2: The interior of the RX350
Fig 2: The interior of the RX350
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Fig 3: The screen design is the same as that of the existing touch panels.
Fig 3: The screen design is the same as that of the existing touch panels.
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Fig 4: The main menu. It is displayed when the "menu" switch is pressed.
Fig 4: The main menu. It is displayed when the "menu" switch is pressed.
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The "Remote Touch," an HMI (human machine interface) for the car navigation system equipped in the "Lexus RX" released by Toyota Motor Corp, was developed by Denso Corp (Fig 1).

The Remote Touch enables to remote-control the car navigation display located in the upper part of the instrument panel via the pointing device installed on the center console. Users place their fingertips on the operating knob to move the pointer on the screen.

The operating knob employs "haptic" technology that adjusts the operational reaction force felt by the driver. The knob was manufactured by Alps Electric Co Ltd, which has already commercialized the haptic technology in its dial-type interface.

The Remote Touch measures 80 (W) x 220 (D) x 95mm (H) and is composed of the operating knob, which is operated by a fingertip to move the pointer up/down and right/left, a device for supporting the palm and switches located on both sides and top of the knob.

Touch panel input functions are replaced by an operating knob and the "ENTER" switch on both sides of the knob. Specifically, the pointer is moved by the operating knob, and the ENTER switch is used for making selections, instead of directly touching the icons on the screen.

The basic design of the screens remains the same as that of the touch panel version so that users familiar with the touch panel operation aren't confused (Fig 3). However, if the pointer moves like the one controlled by a mouse, it is difficult to move the pointer to a certain switch (icon).

To address this issue, the haptic technology was adopted so that the driver can feel like the pointer is gravitating toward the switch.

The operating knob is equipped with two motors and an encoder, and the motors are controlled so that the operating knob will always be in a neutral position after the car navigation is started.

The main menu has five switches lined up horizontally (Fig 4). When the pointer is moved from the "destination" to "information G," for example, the operational reaction force changes on the line that separates the two switches.

To be more specific, the operating knob is drawn toward the left until the pointer reaches the right end of the "destination" switch while it is drawn toward the right until the pointer reaches the left end of the "information G" switch. So the user can feel like crossing a bump when the pointer crosses over the switch.

Because the reaction force varies depending on coordinates on which the pointer is positioned, the user feels as if the pointer gravitates toward the center of a switch when the pointer is inside the coordinates of the switch.

As a result of this effect, the pointer is drawn toward the center of a switch even if it is roughly moved with the fingertip, making it easy to control the position of the pointer. The pointer can be freely moved in the areas where there is no switch.

The Remote Touch will be mounted on the "Lexus HS250h," which Toyota plans to release in the summer of 2009, in addition to the Lexus RX.

Toyota has not made any announcement in respect to the adoption of the Remote Touch for Toyota products other than the Lexus brand vehicles. It is expected to be more expensive than the haptic dials employed by German manufacturers including BMW AG and Daimler AG. Therefore, its adoption, if any, will probably be limited to upper grade models.