How Robotic Massage Chairs Operate

Picture this: after a long, tiring day, you return home. Your back feels tight, your shoulders sore, and your feet ache. You remove your shoes, recline in a chair, and grab the remote. But you're not about to watch TV – you're about to let your chair take care of your discomfort, as it gives you a soothing massage.

Robotic massage chairs have been available for decades. In the U.S., they are considered luxury items, with prices reaching several thousand dollars. Though their popularity is relatively low in the U.S., they are much more common in other parts of the world. Websites suggest that in Japan, over 20 percent of households own a massage chair.

The concept behind robotic massage chairs is straightforward. A device in or on the chair mimics the sensation of a massage. Some chairs feature simple vibrations, while others incorporate advanced mechanisms that replicate the techniques of a professional massage therapist. All are designed to offer comfort and relief to individuals with disposable income.

While many massage chairs rely on mechanical methods, inventors have developed various other approaches to perfect the massage chair experience. Some have created models that use water to ease tension and stress, while others employ airbags to gently squeeze muscles and enhance blood circulation. Many massage chair makers integrate multiple technologies in their designs.

How do these devices operate? Sit back, relax, and set your chair to 'shiatsu' as we walk you through the process, beginning with the mechanical approach.

Massage Chairs: The Mechanical Massage

Most massage chairs incorporate a mix of motors, gears, rollers, and vibrating mechanisms. These types of chairs have been around for more than 50 years and have grown significantly more advanced over recent decades.

The most basic massage chairs use vibrating surfaces to deliver a massage. To create these vibrations, manufacturers use small devices containing an off-center weighted wheel or gear. As the electric motor rotates the wheel quickly, the imbalance causes vibrations. A similar device is found in cell phones with vibrating features. A massage chair requires several of these devices to create vibrations across its surface without destabilizing the chair itself.

While no two manufacturers design their massage chairs exactly the same way, there are common design features found across most models. If you were to remove the upholstery, you'd reveal a framework that holds a series of motors, gears, and rollers.

When you experience a massage in a chair, it's the rollers that simulate a human massage. The rollers move in patterns set by the frame's structure. Some chairs have rollers with limited motion, moving only up and down the chair’s back along a track. Electric motors supply power for the rollers’ movement.

Other massage chairs feature more advanced designs. In these models, the rollers are mounted on a mechanical arm that can move both horizontally and vertically. This allows the rollers to move left, right, or even in circles. The mechanical arm’s movements are also powered by an electric motor, and a microprocessor stores pre-programmed patterns set by the manufacturer.

Many massage chairs offer the ability to adjust the massage intensity. This can be done in two primary ways: by changing the distance the rollers move from the frame during the massage, or by mounting the frame on a pivot in the backrest, allowing it to shift closer or further away from the user's back.

As most massage chairs also function as recliners, manufacturers must design electrical and mechanical systems that can operate in different positions. Some chairs feature a motorized reclining system, allowing users to adjust the chair's angle by pressing a button. Other chairs require the user to pull a release handle and manually lean back to change the position.

Not all massage chairs rely on mechanical components alone. One unique design uses water, yet users remain completely dry. Curious about how it works? Read on to find out.

Staying Dry with Water Massage

An alternative to the purely mechanical approach is the use of water, as demonstrated by the Hydro-Massage Chair designed by Frank J. Arzt. This innovative chair allows users to enjoy a refreshing massage through jets of water, all while staying completely dry.

Arzt's design incorporates a waterproof membrane similar to those found on waterbeds. This membrane is positioned in the backrest of the chair. The side of the membrane that contacts the user's back is secured with a series of bars, which prevent the membrane from distorting when the water pressure inside it changes. Valves at the top of the membrane allow either the user or manufacturer to fill the membrane with water.

Along the back of the membrane, there are several nozzles connected by tubes to an electric pump and a heating and cooling system. The pump circulates the water through the nozzles, creating the massage effect. Users sit back and experience a massage from the water jets, while the heating and cooling system adjusts the water's temperature according to their preferences.

Arzt's patent proposes that the nozzles may contain a rotor within the central passage. As the rotor spins, it causes the water jet to rotate, broadening the massage's impact area. By pulsating the water through the nozzles, the chair can mimic the tapping sensation found in some mechanical massage chairs.

Although Arzt submitted his patent in 2000, the market has not been overwhelmed -- pun intended -- by hydro massage chairs. This could be due to the relatively small market for massage chairs worldwide or possibly because of the complexity of the manufacturing process. However, dry hydro-massage tables and mattresses are already available, which means a chair version could still emerge in the future.

Some massage chairs use a different method that involves air. How do these chairs harness air to ease a sore back? Keep reading to find out more.

Blown Away by Air Massage

A common technique used by massage therapists involves gripping and squeezing large muscle groups firmly for a few seconds before releasing the pressure. This action can help relieve muscle tension, encouraging the muscles to relax. Recognizing this, some massage chair manufacturers saw an opportunity to incorporate these techniques into their own designs. But how can you create a device that applies pressure without making it a potential threat, more suited for a horror film than relaxation?

One effective solution is the use of airbags. Many high-end massage chairs are equipped with multiple airbags. The main focus is typically on the user's arms and legs, as these extremities are easier to target without risking injury or compromising the ability to breathe.

Some massage chairs feature several airbags designed to squeeze each arm and leg. A small air compressor built into the chair inflates the airbags, with the compressor connected to them via a network of pipes or tubes. Certain chairs include a switch that regulates air flow, enabling one set of airbags to inflate independently of the others. Other models may have multiple compressors, each responsible for inflating specific airbags.

A multiprocessor integrated into the chair coordinates with the compressor, controlling when the airbags should inflate during a massage session. Many chairs allow users to adjust the intensity of the air massage, with the pressure increasing as the airbags inflate more fully, providing a firmer squeeze.

Some massage chairs also incorporate airbags in the seat and backrest areas. By rapidly inflating and deflating these airbags, the chair can mimic the tapping sensation typical of some massage techniques. Slower inflation simulates a rolling or kneading motion. However, most massage chairs rely on mechanical methods for the majority of their functions, with airbags serving as a supplementary tool for massage therapy.

Curious about how to control a massage chair, or what makes chairs capable of sensing your body size? The answers are just around the corner in the next section.

Controlling the Massage Chair

Many massage chairs come with a preset menu of massage options. Users can simply sit back and pick whichever therapy they prefer from the list, typically using a remote control. Because these chairs are easy to operate, most remote controls are directly wired to the chair, with minimal need for complex operation.

A microprocessor embedded in the chair stores data for each available massage pattern. When the user selects a specific therapy, the microprocessor sends commands to the chair's different massage mechanisms. While the user can't alter the pre-programmed massage patterns, many chairs allow for adjustments in intensity via the remote control. The microprocessor then directs the relevant apparatus to modify its intensity based on the user's preference.

Some high-end massage chairs feature sophisticated interactive devices. For example, certain models come equipped with an infrared body scanner. These scanners, consisting of multiple infrared sensors, detect where the user's body makes contact with the chair. The data is sent to the microprocessor, which processes the information and sends updated commands to adjust the massage apparatus accordingly.

Given that multiple users may use the same massage chair, it’s essential to allow for individual adjustments. For instance, a six-foot (1.8-meter) user’s back will make contact with a greater area of the backrest than a five-foot (1.5-meter) user. A neck massage aimed at a taller individual would feel out of place for someone much shorter. By scanning the user’s body, the chair adjusts the contact points to fit the person's height and width, ensuring a more personalized experience.

Certain massage chairs are capable of monitoring the user’s responses to the massage, adjusting the intensity and focusing on specific areas as needed. For example, the Sanyo Zero Gravity Massage Chair features sensors that track galvanic skin response, a technology also used in lie detector tests to assess a person’s reaction to questions. The sensors measure changes in pulse rate and perspiration. When the chair detects an increase in these factors, it interprets this as tension or stiffness in the area being massaged and adjusts its pattern accordingly [source: Sanyo].

A handful of massage chairs are equipped with voice-response technology. This software allows the chair to recognize and respond to verbal commands from the user. However, the range of commands it can process is typically limited to a small selection of the chair’s overall capabilities.

Will massage chairs ever transition from being a luxury item to a standard household feature in the United States? Many manufacturers hope so. However, for the time being, the high cost of these chairs seems likely to keep them in the luxury category, limiting their widespread adoption.